diff --git a/.gitignore b/.gitignore
index c88a604..8192af3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -33,3 +33,5 @@ build/
 
 # Docker volumes and data
 postgres_data/
+
+.claude/
\ No newline at end of file
diff --git a/backend/internal/auth/jwt.go b/backend/internal/auth/jwt.go
index 9f4cb84..ddf8e01 100644
--- a/backend/internal/auth/jwt.go
+++ b/backend/internal/auth/jwt.go
@@ -60,4 +60,4 @@ func ValidateJWT(tokenString, secret string) (*UserClaims, error) {
 	}
 
 	return nil, errors.New("invalid token claims")
-}
\ No newline at end of file
+}
diff --git a/backend/internal/auth/middleware.go b/backend/internal/auth/middleware.go
index e5d076f..9789b04 100644
--- a/backend/internal/auth/middleware.go
+++ b/backend/internal/auth/middleware.go
@@ -18,142 +18,142 @@ const ContextUserIDKey = "user_id"
 
 // AuthMiddleware provides auth middleware
 type AuthMiddleware struct {
-    store     store.Store
-    jwtSecret string
+	store     store.Store
+	jwtSecret string
 }
 
 // NewAuthMiddleware creates a new auth middleware
 func NewAuthMiddleware(store store.Store, jwtSecret string) *AuthMiddleware {
-    return &AuthMiddleware{
-        store:     store,
-        jwtSecret: jwtSecret,
-    }
+	return &AuthMiddleware{
+		store:     store,
+		jwtSecret: jwtSecret,
+	}
 }
 
 // RequireAuth middleware requires valid authentication
 func (m *AuthMiddleware) RequireAuth() gin.HandlerFunc {
-    return func(c *gin.Context) {
-        fmt.Println("🔒 RequireAuth: Starting authentication check")
+	return func(c *gin.Context) {
+		fmt.Println("🔒 RequireAuth: Starting authentication check")
 
-        user, claims, err := m.getUserFromToken(c)
+		user, claims, err := m.getUserFromToken(c)
 
-        fmt.Printf("🔒 RequireAuth: user=%v, err=%v\n", user, err)
-        if claims != nil {
-            fmt.Printf("🔒 RequireAuth: claims.Name=%s, claims.Email=%s\n", claims.Name, claims.Email)
-        }
+		fmt.Printf("🔒 RequireAuth: user=%v, err=%v\n", user, err)
+		if claims != nil {
+			fmt.Printf("🔒 RequireAuth: claims.Name=%s, claims.Email=%s\n", claims.Name, claims.Email)
+		}
 
-        if err != nil || user == nil {
-            fmt.Printf("❌ RequireAuth: FAILED - err=%v, user=%v\n", err, user)
-            c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
-            c.Abort()
-            return
-        }
+		if err != nil || user == nil {
+			fmt.Printf("❌ RequireAuth: FAILED - err=%v, user=%v\n", err, user)
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
+			c.Abort()
+			return
+		}
 
-        // Note: Name and Email might be empty for old JWT tokens
-        if claims.Name == "" || claims.Email == "" {
-            fmt.Printf("⚠️  RequireAuth: WARNING - Token missing name/email (using old token format)\n")
-        }
+		// Note: Name and Email might be empty for old JWT tokens
+		if claims.Name == "" || claims.Email == "" {
+			fmt.Printf("⚠️  RequireAuth: WARNING - Token missing name/email (using old token format)\n")
+		}
 
-        fmt.Printf("✅ RequireAuth: SUCCESS - setting context for user %v\n", user)
-        c.Set(ContextUserIDKey, user)
-        c.Set("user_email", claims.Email)
-        c.Set("user_name", claims.Name)
-        if claims.AvatarURL != nil {
-            c.Set("avatar_url", *claims.AvatarURL)
-        }
-        c.Next()
-    }
+		fmt.Printf("✅ RequireAuth: SUCCESS - setting context for user %v\n", user)
+		c.Set(ContextUserIDKey, user)
+		c.Set("user_email", claims.Email)
+		c.Set("user_name", claims.Name)
+		if claims.AvatarURL != nil {
+			c.Set("avatar_url", *claims.AvatarURL)
+		}
+		c.Next()
+	}
 }
 
 // OptionalAuth middleware sets user if authenticated, but doesn't require it
 func (m *AuthMiddleware) OptionalAuth() gin.HandlerFunc {
-    return func(c *gin.Context) {
-        user, claims, _ := m.getUserFromToken(c)
-        if user != nil {
-            c.Set(string(UserContextKey), user)
-            c.Set(ContextUserIDKey, user)
-            if claims != nil {
-                c.Set("user_email", claims.Email)
-                c.Set("user_name", claims.Name)
-                if claims.AvatarURL != nil {
-                    c.Set("avatar_url", *claims.AvatarURL)
-                }
-            }
-        }
-        c.Next()
-    }
+	return func(c *gin.Context) {
+		user, claims, _ := m.getUserFromToken(c)
+		if user != nil {
+			c.Set(string(UserContextKey), user)
+			c.Set(ContextUserIDKey, user)
+			if claims != nil {
+				c.Set("user_email", claims.Email)
+				c.Set("user_name", claims.Name)
+				if claims.AvatarURL != nil {
+					c.Set("avatar_url", *claims.AvatarURL)
+				}
+			}
+		}
+		c.Next()
+	}
 }
 
 // getUserFromToken parses the JWT and returns the UserID and the full Claims (for name/email)
 // 注意：返回值变了，现在返回 (*uuid.UUID, *UserClaims, error)
 func (m *AuthMiddleware) getUserFromToken(c *gin.Context) (*uuid.UUID, *UserClaims, error) {
-    authHeader := c.GetHeader("Authorization")
-    fmt.Printf("🔍 getUserFromToken: Authorization header = '%s'\n", authHeader)
+	authHeader := c.GetHeader("Authorization")
+	fmt.Printf("🔍 getUserFromToken: Authorization header = '%s'\n", authHeader)
 
-    if authHeader == "" {
-        fmt.Println("⚠️  getUserFromToken: No Authorization header")
-        return nil, nil, nil
-    }
+	if authHeader == "" {
+		fmt.Println("⚠️  getUserFromToken: No Authorization header")
+		return nil, nil, nil
+	}
 
-    parts := strings.Split(authHeader, " ")
-    if len(parts) != 2 || parts[0] != "Bearer" {
-        fmt.Printf("⚠️  getUserFromToken: Invalid header format (parts=%d, prefix=%s)\n", len(parts), parts[0])
-        return nil, nil, nil
-    }
+	parts := strings.Split(authHeader, " ")
+	if len(parts) != 2 || parts[0] != "Bearer" {
+		fmt.Printf("⚠️  getUserFromToken: Invalid header format (parts=%d, prefix=%s)\n", len(parts), parts[0])
+		return nil, nil, nil
+	}
 
-    tokenString := parts[1]
-    fmt.Printf("🔍 getUserFromToken: Token = %s...\n", tokenString[:min(20, len(tokenString))])
+	tokenString := parts[1]
+	fmt.Printf("🔍 getUserFromToken: Token = %s...\n", tokenString[:min(20, len(tokenString))])
 
-    token, err := jwt.ParseWithClaims(tokenString, &UserClaims{}, func(token *jwt.Token) (interface{}, error) {
-        // 必须要验证签名算法是 HMAC (HS256)
-        if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
-            return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
-        }
-        return []byte(m.jwtSecret), nil
-    })
+	token, err := jwt.ParseWithClaims(tokenString, &UserClaims{}, func(token *jwt.Token) (interface{}, error) {
+		// 必须要验证签名算法是 HMAC (HS256)
+		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
+		}
+		return []byte(m.jwtSecret), nil
+	})
 
-    if err != nil {
-        fmt.Printf("❌ getUserFromToken: JWT parse error: %v\n", err)
-        return nil, nil, err
-    }
+	if err != nil {
+		fmt.Printf("❌ getUserFromToken: JWT parse error: %v\n", err)
+		return nil, nil, err
+	}
 
-    // 2. 验证 Token 有效性并提取 Claims
-    if claims, ok := token.Claims.(*UserClaims); ok && token.Valid {
-        // 3. 把 String 类型的 Subject 转回 UUID
-        // 因为我们在 GenerateJWT 里存的是 claims.Subject = userID.String()
-        userID, err := uuid.Parse(claims.Subject)
-        if err != nil {
-            fmt.Printf("❌ getUserFromToken: Invalid UUID in subject: %v\n", err)
-            return nil, nil, fmt.Errorf("invalid user ID in token")
-        }
+	// 2. 验证 Token 有效性并提取 Claims
+	if claims, ok := token.Claims.(*UserClaims); ok && token.Valid {
+		// 3. 把 String 类型的 Subject 转回 UUID
+		// 因为我们在 GenerateJWT 里存的是 claims.Subject = userID.String()
+		userID, err := uuid.Parse(claims.Subject)
+		if err != nil {
+			fmt.Printf("❌ getUserFromToken: Invalid UUID in subject: %v\n", err)
+			return nil, nil, fmt.Errorf("invalid user ID in token")
+		}
 
-        // 成功！直接返回 UUID 和 claims (里面包含 Name 和 Email)
-        // 这一步完全没有查数据库，速度极快
-        fmt.Printf("✅ getUserFromToken: SUCCESS - userID=%v, name=%s, email=%s\n", userID, claims.Name, claims.Email)
-        return &userID, claims, nil
-    }
+		// 成功！直接返回 UUID 和 claims (里面包含 Name 和 Email)
+		// 这一步完全没有查数据库，速度极快
+		fmt.Printf("✅ getUserFromToken: SUCCESS - userID=%v, name=%s, email=%s\n", userID, claims.Name, claims.Email)
+		return &userID, claims, nil
+	}
 
-    fmt.Println("❌ getUserFromToken: Invalid token claims or token not valid")
-    return nil, nil, fmt.Errorf("invalid token claims")
+	fmt.Println("❌ getUserFromToken: Invalid token claims or token not valid")
+	return nil, nil, fmt.Errorf("invalid token claims")
 }
 
 // GetUserFromContext extracts user ID from context
 func GetUserFromContext(c *gin.Context) *uuid.UUID {
-    // 修正点：使用和存入时完全一样的 Key
-    val, exists := c.Get(ContextUserIDKey)
-    fmt.Println("within getFromContext the id is ... ")
-    fmt.Println(val);
-    if !exists {
-        return nil
-    }
+	// 修正点：使用和存入时完全一样的 Key
+	val, exists := c.Get(ContextUserIDKey)
+	fmt.Println("within getFromContext the id is ... ")
+	fmt.Println(val)
+	if !exists {
+		return nil
+	}
 
-    // 修正点：断言为 *uuid.UUID (因为我们在中间件里存的就是这个类型)
-    uid, ok := val.(*uuid.UUID)
-    if !ok {
-        return nil
-    }
+	// 修正点：断言为 *uuid.UUID (因为我们在中间件里存的就是这个类型)
+	uid, ok := val.(*uuid.UUID)
+	if !ok {
+		return nil
+	}
 
-    return uid
+	return uid
 }
 
 // ValidateToken validates a JWT token and returns user ID, name, and avatar URL from JWT claims
diff --git a/backend/internal/auth/oauth.go b/backend/internal/auth/oauth.go
index 5dad179..1a5a887 100644
--- a/backend/internal/auth/oauth.go
+++ b/backend/internal/auth/oauth.go
@@ -8,25 +8,25 @@ import (
 
 // GetGoogleOAuthConfig returns Google OAuth2 config
 func GetGoogleOAuthConfig(clientID, clientSecret, redirectURL string) *oauth2.Config {
-    return &oauth2.Config{
-        ClientID:     clientID,
-        ClientSecret: clientSecret,
-        RedirectURL:  redirectURL,
-        Scopes: []string{
-            "https://www.googleapis.com/auth/userinfo.email",
-            "https://www.googleapis.com/auth/userinfo.profile",
-        },
-        Endpoint: google.Endpoint,
-    }
+	return &oauth2.Config{
+		ClientID:     clientID,
+		ClientSecret: clientSecret,
+		RedirectURL:  redirectURL,
+		Scopes: []string{
+			"https://www.googleapis.com/auth/userinfo.email",
+			"https://www.googleapis.com/auth/userinfo.profile",
+		},
+		Endpoint: google.Endpoint,
+	}
 }
 
 // GetGitHubOAuthConfig returns GitHub OAuth2 config
 func GetGitHubOAuthConfig(clientID, clientSecret, redirectURL string) *oauth2.Config {
-    return &oauth2.Config{
-        ClientID:     clientID,
-        ClientSecret: clientSecret,
-        RedirectURL:  redirectURL,
-        Scopes:       []string{"user:email"},
-        Endpoint:     github.Endpoint,
-    }
+	return &oauth2.Config{
+		ClientID:     clientID,
+		ClientSecret: clientSecret,
+		RedirectURL:  redirectURL,
+		Scopes:       []string{"user:email"},
+		Endpoint:     github.Endpoint,
+	}
 }
diff --git a/backend/internal/handlers/auth.go b/backend/internal/handlers/auth.go
index bd515fc..687b7d7 100644
--- a/backend/internal/handlers/auth.go
+++ b/backend/internal/handlers/auth.go
@@ -64,10 +64,10 @@ func (h *AuthHandler) GoogleLogin(c *gin.Context) {
 // GoogleCallback handles Google OAuth callback
 func (h *AuthHandler) GoogleCallback(c *gin.Context) {
 	oauthState, err := c.Cookie("oauthstate")
-    if err != nil || c.Query("state") != oauthState {
-        c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid oauth state"})
-        return
-    }
+	if err != nil || c.Query("state") != oauthState {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid oauth state"})
+		return
+	}
 	log.Println("Google callback state:", c.Query("state"))
 	// Exchange code for token
 	token, err := h.googleConfig.Exchange(c.Request.Context(), c.Query("code"))
@@ -94,11 +94,11 @@ func (h *AuthHandler) GoogleCallback(c *gin.Context) {
 		Name    string `json:"name"`
 		Picture string `json:"picture"`
 	}
-	
+
 	if err := json.Unmarshal(data, &userInfo); err != nil {
-    log.Printf("Failed to parse Google response: %v | Data: %s", err, string(data))
-    c.JSON(http.StatusInternalServerError, gin.H{"error": "Invalid Google response"})
-    return
+		log.Printf("Failed to parse Google response: %v | Data: %s", err, string(data))
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Invalid Google response"})
+		return
 	}
 	log.Println("Google user info:", userInfo)
 	// Upsert user in database
@@ -118,10 +118,10 @@ func (h *AuthHandler) GoogleCallback(c *gin.Context) {
 	// Create session and JWT
 	jwt, err := h.createSessionAndJWT(c, user)
 	if err != nil {
-		fmt.Printf("❌ DATABASE ERROR: %v\n", err) 
-        c.JSON(http.StatusInternalServerError, gin.H{
-            "error": fmt.Sprintf("CreateSession Error: %v", err), 
-        })
+		fmt.Printf("❌ DATABASE ERROR: %v\n", err)
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"error": fmt.Sprintf("CreateSession Error: %v", err),
+		})
 		return
 	}
 
@@ -140,10 +140,10 @@ func (h *AuthHandler) GithubLogin(c *gin.Context) {
 // GithubCallback handles GitHub OAuth callback
 func (h *AuthHandler) GithubCallback(c *gin.Context) {
 	oauthState, err := c.Cookie("oauthstate")
-    if err != nil || c.Query("state") != oauthState {
-        c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid oauth state"})
-        return
-    }
+	if err != nil || c.Query("state") != oauthState {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid oauth state"})
+		return
+	}
 	log.Println("Github callback state:", c.Query("state"))
 	code := c.Query("code")
 	if code == "" {
@@ -160,7 +160,7 @@ func (h *AuthHandler) GithubCallback(c *gin.Context) {
 
 	// Get user info from GitHub
 	client := h.githubConfig.Client(c.Request.Context(), token)
-	
+
 	// Get user profile
 	resp, err := client.Get("https://api.github.com/user")
 	if err != nil {
@@ -178,10 +178,10 @@ func (h *AuthHandler) GithubCallback(c *gin.Context) {
 		AvatarURL string `json:"avatar_url"`
 	}
 	if err := json.Unmarshal(data, &userInfo); err != nil {
-    log.Printf("Failed to parse GitHub response: %v | Data: %s", err, string(data))
-    c.JSON(http.StatusInternalServerError, gin.H{"error": "Invalid GitHub response"})
-    return
-}
+		log.Printf("Failed to parse GitHub response: %v | Data: %s", err, string(data))
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Invalid GitHub response"})
+		return
+	}
 
 	// If email is not public, fetch it separately
 	if userInfo.Email == "" {
@@ -315,10 +315,10 @@ func (h *AuthHandler) generateStateOauthCookie(w http.ResponseWriter) string {
 		Name:     "oauthstate",
 		Value:    state,
 		Expires:  time.Now().Add(10 * time.Minute),
-		HttpOnly: true,                   // Prevents JavaScript access (XSS protection)
-		Secure:   h.cfg.SecureCookie,     // true in production, false for localhost
-		SameSite: http.SameSiteLaxMode,   // Allows same-site OAuth redirects
-		Path:     "/",                    // Ensures cookie is sent to all backend paths
+		HttpOnly: true,                 // Prevents JavaScript access (XSS protection)
+		Secure:   h.cfg.SecureCookie,   // true in production, false for localhost
+		SameSite: http.SameSiteLaxMode, // Allows same-site OAuth redirects
+		Path:     "/",                  // Ensures cookie is sent to all backend paths
 	}
 	http.SetCookie(w, &cookie)
 
diff --git a/backend/internal/handlers/document.go b/backend/internal/handlers/document.go
index cecb183..3069885 100644
--- a/backend/internal/handlers/document.go
+++ b/backend/internal/handlers/document.go
@@ -11,16 +11,15 @@ import (
 	"github.com/google/uuid"
 )
 
-  type DocumentHandler struct {
-  	store *store.PostgresStore
-  }
+type DocumentHandler struct {
+	store *store.PostgresStore
+}
 
-  func NewDocumentHandler(s *store.PostgresStore) *DocumentHandler {
-  	return &DocumentHandler{store: s}
-  }
+func NewDocumentHandler(s *store.PostgresStore) *DocumentHandler {
+	return &DocumentHandler{store: s}
+}
 
-
-  // CreateDocument creates a new document (requires auth)
+// CreateDocument creates a new document (requires auth)
 func (h *DocumentHandler) CreateDocument(c *gin.Context) {
 	userID := auth.GetUserFromContext(c)
 	if userID == nil {
@@ -44,7 +43,7 @@ func (h *DocumentHandler) CreateDocument(c *gin.Context) {
 	c.JSON(http.StatusCreated, doc)
 }
 
-  func (h *DocumentHandler) ListDocuments(c *gin.Context) {
+func (h *DocumentHandler) ListDocuments(c *gin.Context) {
 	userID := auth.GetUserFromContext(c)
 	fmt.Println("Getting userId, which is : ")
 	fmt.Println(userID)
@@ -66,8 +65,7 @@ func (h *DocumentHandler) CreateDocument(c *gin.Context) {
 	})
 }
 
-
-  func (h *DocumentHandler) GetDocument(c *gin.Context) {
+func (h *DocumentHandler) GetDocument(c *gin.Context) {
 	id, err := uuid.Parse(c.Param("id"))
 	if err != nil {
 		respondBadRequest(c, "Invalid document ID format")
@@ -104,8 +102,9 @@ func (h *DocumentHandler) CreateDocument(c *gin.Context) {
 
 	c.JSON(http.StatusOK, doc)
 }
-  // GetDocumentState returns the Yjs state for a document
-  // GetDocumentState retrieves document state (requires view permission)
+
+// GetDocumentState returns the Yjs state for a document
+// GetDocumentState retrieves document state (requires view permission)
 func (h *DocumentHandler) GetDocumentState(c *gin.Context) {
 	id, err := uuid.Parse(c.Param("id"))
 	if err != nil {
@@ -143,7 +142,7 @@ func (h *DocumentHandler) GetDocumentState(c *gin.Context) {
 	c.Data(http.StatusOK, "application/octet-stream", state)
 }
 
-  // UpdateDocumentState updates document state (requires edit permission)
+// UpdateDocumentState updates document state (requires edit permission)
 func (h *DocumentHandler) UpdateDocumentState(c *gin.Context) {
 	id, err := uuid.Parse(c.Param("id"))
 	if err != nil {
@@ -195,7 +194,7 @@ func (h *DocumentHandler) UpdateDocumentState(c *gin.Context) {
 	c.JSON(http.StatusOK, gin.H{"message": "State updated successfully"})
 }
 
-  // DeleteDocument deletes a document (owner only)
+// DeleteDocument deletes a document (owner only)
 func (h *DocumentHandler) DeleteDocument(c *gin.Context) {
 	id, err := uuid.Parse(c.Param("id"))
 	if err != nil {
@@ -237,107 +236,109 @@ func (h *DocumentHandler) DeleteDocument(c *gin.Context) {
 
 // GetDocumentPermission returns the user's permission level for a document
 func (h *DocumentHandler) GetDocumentPermission(c *gin.Context) {
-    documentID, err := uuid.Parse(c.Param("id"))
-    if err != nil {
-        respondBadRequest(c, "Invalid document ID format")
-        return
-    }
+	documentID, err := uuid.Parse(c.Param("id"))
+	if err != nil {
+		respondBadRequest(c, "Invalid document ID format")
+		return
+	}
 
-    // 1. 先检查文档是否存在 (Good practice)
-    _, err = h.store.GetDocument(documentID)
-    if err != nil {
-        respondNotFound(c, "document")
-        return
-    }
+	// 1. 先检查文档是否存在 (Good practice)
+	_, err = h.store.GetDocument(documentID)
+	if err != nil {
+		respondNotFound(c, "document")
+		return
+	}
 
-    userID := auth.GetUserFromContext(c)
-    shareToken := c.Query("share")
+	userID := auth.GetUserFromContext(c)
+	shareToken := c.Query("share")
 
-    // 定义两个临时变量，用来存两边的结果
-    var userPerm string  // 存 document_shares 的结果
-    var tokenPerm string // 存 share_token 的结果
+	// 定义两个临时变量，用来存两边的结果
+	var userPerm string  // 存 document_shares 的结果
+	var tokenPerm string // 存 share_token 的结果
 
-    // ====================================================
-    // 步骤 A: 检查个人权限 (Base Permission)
-    // ====================================================
-    if userID != nil {
-        perm, err := h.store.GetUserPermission(c.Request.Context(), documentID, *userID)
-        if err != nil {
-            respondInternalError(c, "Failed to get user permission", err)
-            return
-        }
-        userPerm = perm 
-        // ⚠️ 注意：如果 perm 是空，这里不报错！继续往下走！
-    }
+	// ====================================================
+	// 步骤 A: 检查个人权限 (Base Permission)
+	// ====================================================
+	if userID != nil {
+		perm, err := h.store.GetUserPermission(c.Request.Context(), documentID, *userID)
+		if err != nil {
+			respondInternalError(c, "Failed to get user permission", err)
+			return
+		}
+		userPerm = perm
+		// ⚠️ 注意：如果 perm 是空，这里不报错！继续往下走！
+	}
 
-    // ====================================================
-    // 步骤 B: 检查 Token 权限 (Upgrade Permission)
-    // ====================================================
-    if shareToken != "" {
-        // 先验证 Token 是否有效
-        valid, err := h.store.ValidateShareToken(c.Request.Context(), documentID, shareToken)
-        if err != nil {
-            respondInternalError(c, "Failed to validate token", err)
-            return
-        }
-        
-        // 只有 Token 有效才去取权限
-        if valid {
-            p, err := h.store.GetShareLinkPermission(c.Request.Context(), documentID)
-            if err != nil {
-                respondInternalError(c, "Failed to get token permission", err)
-                return
-            }
-            tokenPerm = p
-            // 处理数据库老数据的 fallback
-            if tokenPerm == "" { tokenPerm = "view" } 
-        }
-    }
+	// ====================================================
+	// 步骤 B: 检查 Token 权限 (Upgrade Permission)
+	// ====================================================
+	if shareToken != "" {
+		// 先验证 Token 是否有效
+		valid, err := h.store.ValidateShareToken(c.Request.Context(), documentID, shareToken)
+		if err != nil {
+			respondInternalError(c, "Failed to validate token", err)
+			return
+		}
 
-    // ====================================================
-    // 步骤 C: ⚡️ 权限合并与计算 (The Brain)
-    // ====================================================
-    
-    finalPermission := ""
-    role := "viewer" // 默认角色
+		// 只有 Token 有效才去取权限
+		if valid {
+			p, err := h.store.GetShareLinkPermission(c.Request.Context(), documentID)
+			if err != nil {
+				respondInternalError(c, "Failed to get token permission", err)
+				return
+			}
+			tokenPerm = p
+			// 处理数据库老数据的 fallback
+			if tokenPerm == "" {
+				tokenPerm = "view"
+			}
+		}
+	}
 
-    // 1. 如果是 Owner，无敌，直接返回
-    if userPerm == "owner" {
-        finalPermission = "edit"
-        role = "owner"
-        // 直接返回，不用看 Token 了
-        c.JSON(http.StatusOK, models.PermissionResponse{
-            Permission: finalPermission,
-            Role:       role,
-        })
-        return
-    }
+	// ====================================================
+	// 步骤 C: ⚡️ 权限合并与计算 (The Brain)
+	// ====================================================
 
-    // 2. 比较 User 和 Token，取最大值
-    // 逻辑：只要任意一边给了 "edit"，那就是 "edit"
-    if userPerm == "edit" || tokenPerm == "edit" {
-        finalPermission = "edit"
-        role = "editor"
-    } else if userPerm == "view" || tokenPerm == "view" {
-        finalPermission = "view"
-        role = "viewer"
-    }
+	finalPermission := ""
+	role := "viewer" // 默认角色
 
-    // ====================================================
-    // 步骤 D: 最终判决
-    // ====================================================
-    if finalPermission == "" {
-        // 既没个人权限，Token 也不对（或者没 Token）
-        if userID == nil {
-             respondUnauthorized(c, "Authentication required") // 没登录且没Token
-        } else {
-             respondForbidden(c, "You don't have permission") // 登录了但没权限
-        }
-        return
-    }
+	// 1. 如果是 Owner，无敌，直接返回
+	if userPerm == "owner" {
+		finalPermission = "edit"
+		role = "owner"
+		// 直接返回，不用看 Token 了
+		c.JSON(http.StatusOK, models.PermissionResponse{
+			Permission: finalPermission,
+			Role:       role,
+		})
+		return
+	}
 
-    c.JSON(http.StatusOK, models.PermissionResponse{
-        Permission: finalPermission,
-        Role:       role,
-    })
-}
\ No newline at end of file
+	// 2. 比较 User 和 Token，取最大值
+	// 逻辑：只要任意一边给了 "edit"，那就是 "edit"
+	if userPerm == "edit" || tokenPerm == "edit" {
+		finalPermission = "edit"
+		role = "editor"
+	} else if userPerm == "view" || tokenPerm == "view" {
+		finalPermission = "view"
+		role = "viewer"
+	}
+
+	// ====================================================
+	// 步骤 D: 最终判决
+	// ====================================================
+	if finalPermission == "" {
+		// 既没个人权限，Token 也不对（或者没 Token）
+		if userID == nil {
+			respondUnauthorized(c, "Authentication required") // 没登录且没Token
+		} else {
+			respondForbidden(c, "You don't have permission") // 登录了但没权限
+		}
+		return
+	}
+
+	c.JSON(http.StatusOK, models.PermissionResponse{
+		Permission: finalPermission,
+		Role:       role,
+	})
+}
diff --git a/backend/internal/handlers/errors.go b/backend/internal/handlers/errors.go
index 1dd67c1..1739705 100644
--- a/backend/internal/handlers/errors.go
+++ b/backend/internal/handlers/errors.go
@@ -91,5 +91,5 @@ func respondInternalError(c *gin.Context, message string, err error) {
 	respondWithError(c, http.StatusInternalServerError, "internal_error", message)
 }
 func respondInvalidID(c *gin.Context, message string) {
-    respondWithError(c, http.StatusBadRequest, "invalid_id", message)
+	respondWithError(c, http.StatusBadRequest, "invalid_id", message)
 }
diff --git a/backend/internal/handlers/share.go b/backend/internal/handlers/share.go
index 4ab0bbf..0260a6d 100644
--- a/backend/internal/handlers/share.go
+++ b/backend/internal/handlers/share.go
@@ -153,6 +153,7 @@ func (h *ShareHandler) DeleteShare(c *gin.Context) {
 
 	c.Status(204)
 }
+
 // CreateShareLink generates a public share link
 func (h *ShareHandler) CreateShareLink(c *gin.Context) {
 	documentID, err := uuid.Parse(c.Param("id"))
@@ -290,4 +291,4 @@ func (h *ShareHandler) RevokeShareLink(c *gin.Context) {
 
 	// c.JSON(http.StatusOK, gin.H{"message": "Share link revoked successfully"})
 	c.Status(204)
-}
\ No newline at end of file
+}
diff --git a/backend/internal/handlers/share_test.go b/backend/internal/handlers/share_test.go
index 64d88da..6607825 100644
--- a/backend/internal/handlers/share_test.go
+++ b/backend/internal/handlers/share_test.go
@@ -70,7 +70,7 @@ func TestShareHandlerSuite(t *testing.T) {
 
 func (s *ShareHandlerSuite) TestCreateShare_ViewPermission() {
 	body := map[string]interface{}{
-		"user_email":      "bob@test.com",
+		"user_email": "bob@test.com",
 		"permission": "view",
 	}
 
@@ -87,7 +87,7 @@ func (s *ShareHandlerSuite) TestCreateShare_ViewPermission() {
 
 func (s *ShareHandlerSuite) TestCreateShare_EditPermission() {
 	body := map[string]interface{}{
-		"user_email":      "bob@test.com",
+		"user_email": "bob@test.com",
 		"permission": "edit",
 	}
 
@@ -104,7 +104,7 @@ func (s *ShareHandlerSuite) TestCreateShare_EditPermission() {
 
 func (s *ShareHandlerSuite) TestCreateShare_NonOwnerDenied() {
 	body := map[string]interface{}{
-		"user_email":      "charlie@test.com",
+		"user_email": "charlie@test.com",
 		"permission": "view",
 	}
 
@@ -118,7 +118,7 @@ func (s *ShareHandlerSuite) TestCreateShare_NonOwnerDenied() {
 
 func (s *ShareHandlerSuite) TestCreateShare_UserNotFound() {
 	body := map[string]interface{}{
-		"user_email":      "nonexistent@test.com",
+		"user_email": "nonexistent@test.com",
 		"permission": "view",
 	}
 
@@ -131,7 +131,7 @@ func (s *ShareHandlerSuite) TestCreateShare_UserNotFound() {
 
 func (s *ShareHandlerSuite) TestCreateShare_InvalidPermission() {
 	body := map[string]interface{}{
-		"user_email":      "bob@test.com",
+		"user_email": "bob@test.com",
 		"permission": "admin", // Invalid permission
 	}
 
@@ -145,7 +145,7 @@ func (s *ShareHandlerSuite) TestCreateShare_InvalidPermission() {
 func (s *ShareHandlerSuite) TestCreateShare_UpdatesExisting() {
 	// Create initial share with view permission
 	body := map[string]interface{}{
-		"user_email":      "bob@test.com",
+		"user_email": "bob@test.com",
 		"permission": "view",
 	}
 
@@ -169,7 +169,7 @@ func (s *ShareHandlerSuite) TestCreateShare_UpdatesExisting() {
 
 func (s *ShareHandlerSuite) TestCreateShare_Unauthorized() {
 	body := map[string]interface{}{
-		"user_email":      "bob@test.com",
+		"user_email": "bob@test.com",
 		"permission": "view",
 	}
 
@@ -182,7 +182,7 @@ func (s *ShareHandlerSuite) TestCreateShare_Unauthorized() {
 
 func (s *ShareHandlerSuite) TestCreateShare_InvalidDocumentID() {
 	body := map[string]interface{}{
-		"user_email":      "bob@test.com",
+		"user_email": "bob@test.com",
 		"permission": "view",
 	}
 
@@ -206,8 +206,8 @@ func (s *ShareHandlerSuite) TestListShares_OwnerSeesAll() {
 	s.assertSuccessResponse(w, http.StatusOK)
 
 	var response models.ShareListResponse
-s.parseJSONResponse(w, &response)
-shares := response.Shares
+	s.parseJSONResponse(w, &response)
+	shares := response.Shares
 	s.GreaterOrEqual(len(shares), 1, "Should have at least one share")
 }
 
@@ -229,8 +229,8 @@ func (s *ShareHandlerSuite) TestListShares_EmptyList() {
 	s.assertSuccessResponse(w, http.StatusOK)
 
 	var response models.ShareListResponse
-s.parseJSONResponse(w, &response)
-shares := response.Shares
+	s.parseJSONResponse(w, &response)
+	shares := response.Shares
 	s.Equal(0, len(shares), "Should have no shares")
 }
 
@@ -243,8 +243,8 @@ func (s *ShareHandlerSuite) TestListShares_IncludesUserDetails() {
 	s.assertSuccessResponse(w, http.StatusOK)
 
 	var response models.ShareListResponse
-s.parseJSONResponse(w, &response)
-shares := response.Shares
+	s.parseJSONResponse(w, &response)
+	shares := response.Shares
 
 	if len(shares) > 0 {
 		share := shares[0]
@@ -266,7 +266,7 @@ func (s *ShareHandlerSuite) TestListShares_OrderedByCreatedAt() {
 	users := []string{"bob@test.com", "charlie@test.com"}
 	for _, email := range users {
 		body := map[string]interface{}{
-			"user_email":      email,
+			"user_email": email,
 			"permission": "view",
 		}
 		w, httpReq, err := s.makeAuthRequest("POST", fmt.Sprintf("/api/documents/%s/shares", s.testData.AlicePrivateDoc), body, s.testData.AliceID)
diff --git a/backend/internal/handlers/websocket_loadtest.go b/backend/internal/handlers/websocket_loadtest.go
index bcb285e..bf5c05d 100644
--- a/backend/internal/handlers/websocket_loadtest.go
+++ b/backend/internal/handlers/websocket_loadtest.go
@@ -48,10 +48,10 @@ func (wsh *WebSocketHandler) HandleWebSocketLoadTest(c *gin.Context) {
 	clientID := uuid.New().String()
 	client := hub.NewClient(
 		clientID,
-		nil,           // userID - nil for anonymous
-		userName,      // userName
-		nil,           // userAvatar
-		"edit",        // permission - full access for load testing
+		nil,      // userID - nil for anonymous
+		userName, // userName
+		nil,      // userAvatar
+		"edit",   // permission - full access for load testing
 		conn,
 		wsh.hub,
 		roomID,
diff --git a/backend/internal/models/document.go b/backend/internal/models/document.go
index 7fe6e10..e0c8029 100644
--- a/backend/internal/models/document.go
+++ b/backend/internal/models/document.go
@@ -14,28 +14,26 @@ const (
 )
 
 type Document struct {
-    ID        uuid.UUID     `json:"id"`
-    Name      string        `json:"name"`
-    Type      DocumentType  `json:"type"`
-    YjsState  []byte        `json:"-"`
-    OwnerID   *uuid.UUID    `json:"owner_id"` // NEW
-    Is_Public bool          `json:"is_public"`
-    CreatedAt time.Time     `json:"created_at"`
-    UpdatedAt time.Time     `json:"updated_at"`
+	ID        uuid.UUID    `json:"id"`
+	Name      string       `json:"name"`
+	Type      DocumentType `json:"type"`
+	YjsState  []byte       `json:"-"`
+	OwnerID   *uuid.UUID   `json:"owner_id"` // NEW
+	Is_Public bool         `json:"is_public"`
+	CreatedAt time.Time    `json:"created_at"`
+	UpdatedAt time.Time    `json:"updated_at"`
 }
 
-
 type CreateDocumentRequest struct {
-  	Name string       `json:"name" binding:"required"`
-  	Type DocumentType `json:"type" binding:"required"`
-  }
+	Name string       `json:"name" binding:"required"`
+	Type DocumentType `json:"type" binding:"required"`
+}
 
-  type UpdateStateRequest struct {
-  	State []byte `json:"state" binding:"required"`
-  }
-
-  type DocumentListResponse struct {
-  	Documents []Document `json:"documents"`
-  	Total     int        `json:"total"`
-  }
+type UpdateStateRequest struct {
+	State []byte `json:"state" binding:"required"`
+}
 
+type DocumentListResponse struct {
+	Documents []Document `json:"documents"`
+	Total     int        `json:"total"`
+}
diff --git a/backend/internal/models/share.go b/backend/internal/models/share.go
index 69637d7..effab6b 100644
--- a/backend/internal/models/share.go
+++ b/backend/internal/models/share.go
@@ -7,30 +7,30 @@ import (
 )
 
 type DocumentShare struct {
-    ID         uuid.UUID  `json:"id"`
-    DocumentID uuid.UUID  `json:"document_id"`
-    UserID     uuid.UUID  `json:"user_id"`
-    Permission string     `json:"permission"` // "view" or "edit"
-    CreatedAt  time.Time  `json:"created_at"`
-    CreatedBy  *uuid.UUID `json:"created_by"`
+	ID         uuid.UUID  `json:"id"`
+	DocumentID uuid.UUID  `json:"document_id"`
+	UserID     uuid.UUID  `json:"user_id"`
+	Permission string     `json:"permission"` // "view" or "edit"
+	CreatedAt  time.Time  `json:"created_at"`
+	CreatedBy  *uuid.UUID `json:"created_by"`
 }
 
 type CreateShareRequest struct {
-    UserEmail  string `json:"user_email" binding:"required"`
-    Permission string `json:"permission" binding:"required,oneof=view edit"`
+	UserEmail  string `json:"user_email" binding:"required"`
+	Permission string `json:"permission" binding:"required,oneof=view edit"`
 }
 
 type ShareListResponse struct {
-    Shares []DocumentShareWithUser `json:"shares"`
+	Shares []DocumentShareWithUser `json:"shares"`
 }
 
 type DocumentShareWithUser struct {
-    DocumentShare
-    User User `json:"user"`
+	DocumentShare
+	User User `json:"user"`
 }
 
 // PermissionResponse represents the user's permission level for a document
 type PermissionResponse struct {
-    Permission string `json:"permission"` // "view" or "edit"
-    Role       string `json:"role"`       // "owner", "editor", or "viewer"
+	Permission string `json:"permission"` // "view" or "edit"
+	Role       string `json:"role"`       // "owner", "editor", or "viewer"
 }
diff --git a/backend/internal/models/user.go b/backend/internal/models/user.go
index 3a1bbc6..2e2aa6b 100644
--- a/backend/internal/models/user.go
+++ b/backend/internal/models/user.go
@@ -7,42 +7,42 @@ import (
 )
 
 type User struct {
-    ID             uuid.UUID  `json:"id"`
-    Email          string     `json:"email"`
-    Name           string     `json:"name"`
-    AvatarURL      *string    `json:"avatar_url"`
-    Provider       string     `json:"provider"`
-    ProviderUserID string     `json:"-"` // Don't expose
-    CreatedAt      time.Time  `json:"created_at"`
-    UpdatedAt      time.Time  `json:"updated_at"`
-    LastLoginAt    *time.Time `json:"last_login_at"`
+	ID             uuid.UUID  `json:"id"`
+	Email          string     `json:"email"`
+	Name           string     `json:"name"`
+	AvatarURL      *string    `json:"avatar_url"`
+	Provider       string     `json:"provider"`
+	ProviderUserID string     `json:"-"` // Don't expose
+	CreatedAt      time.Time  `json:"created_at"`
+	UpdatedAt      time.Time  `json:"updated_at"`
+	LastLoginAt    *time.Time `json:"last_login_at"`
 }
 
 type Session struct {
-    ID        uuid.UUID `json:"id"`
-    UserID    uuid.UUID `json:"user_id"`
-    TokenHash string    `json:"-"` // SHA-256 hash of JWT
-    ExpiresAt time.Time `json:"expires_at"`
-    CreatedAt time.Time `json:"created_at"`
-    UserAgent *string   `json:"user_agent"`
-    IPAddress *string   `json:"ip_address"`
+	ID        uuid.UUID `json:"id"`
+	UserID    uuid.UUID `json:"user_id"`
+	TokenHash string    `json:"-"` // SHA-256 hash of JWT
+	ExpiresAt time.Time `json:"expires_at"`
+	CreatedAt time.Time `json:"created_at"`
+	UserAgent *string   `json:"user_agent"`
+	IPAddress *string   `json:"ip_address"`
 }
 
 type OAuthToken struct {
-    ID           uuid.UUID  `json:"id"`
-    UserID       uuid.UUID  `json:"user_id"`
-    Provider     string     `json:"provider"`
-    AccessToken  string     `json:"-"` // Don't expose
-    RefreshToken *string    `json:"-"`
-    TokenType    string     `json:"token_type"`
-    ExpiresAt    time.Time  `json:"expires_at"`
-    Scope        *string    `json:"scope"`
-    CreatedAt    time.Time  `json:"created_at"`
-    UpdatedAt    time.Time  `json:"updated_at"`
+	ID           uuid.UUID `json:"id"`
+	UserID       uuid.UUID `json:"user_id"`
+	Provider     string    `json:"provider"`
+	AccessToken  string    `json:"-"` // Don't expose
+	RefreshToken *string   `json:"-"`
+	TokenType    string    `json:"token_type"`
+	ExpiresAt    time.Time `json:"expires_at"`
+	Scope        *string   `json:"scope"`
+	CreatedAt    time.Time `json:"created_at"`
+	UpdatedAt    time.Time `json:"updated_at"`
 }
 
 // Response for /auth/me endpoint
 type UserResponse struct {
-    User  *User `json:"user"`
-    Token string `json:"token,omitempty"`
+	User  *User  `json:"user"`
+	Token string `json:"token,omitempty"`
 }
diff --git a/backend/internal/models/version.go b/backend/internal/models/version.go
index 4753ff7..d0ba924 100644
--- a/backend/internal/models/version.go
+++ b/backend/internal/models/version.go
@@ -10,8 +10,8 @@ import (
 type DocumentVersion struct {
 	ID              uuid.UUID  `json:"id"`
 	DocumentID      uuid.UUID  `json:"document_id"`
-	YjsSnapshot     []byte     `json:"-"`                    // Omit from JSON (binary)
-	TextPreview     *string    `json:"text_preview"`         // Full plain text
+	YjsSnapshot     []byte     `json:"-"`            // Omit from JSON (binary)
+	TextPreview     *string    `json:"text_preview"` // Full plain text
 	VersionNumber   int        `json:"version_number"`
 	CreatedBy       *uuid.UUID `json:"created_by"`
 	VersionLabel    *string    `json:"version_label"`
diff --git a/backend/internal/store/postgres.go b/backend/internal/store/postgres.go
index 01974e6..fe46d35 100644
--- a/backend/internal/store/postgres.go
+++ b/backend/internal/store/postgres.go
@@ -13,33 +13,33 @@ import (
 
 // Store interface defines all database operations
 type Store interface {
-    // Document operations
-    CreateDocument(name string, docType models.DocumentType) (*models.Document, error)
-    CreateDocumentWithOwner(name string, docType models.DocumentType, ownerID *uuid.UUID) (*models.Document, error)  // ADD THIS
-    GetDocument(id uuid.UUID) (*models.Document, error)
-    ListDocuments() ([]models.Document, error)
-    ListUserDocuments(ctx context.Context, userID uuid.UUID) ([]models.Document, error)  // ADD THIS
-    UpdateDocumentState(id uuid.UUID, state []byte) error
-    DeleteDocument(id uuid.UUID) error
-    
-    // User operations
-    UpsertUser(ctx context.Context, provider, providerUserID, email, name string, avatarURL *string) (*models.User, error)
-    GetUserByID(ctx context.Context, userID uuid.UUID) (*models.User, error)
-    GetUserByEmail(ctx context.Context, email string) (*models.User, error)
-    
-    // Session operations
-    CreateSession(ctx context.Context, userID uuid.UUID, sessionID uuid.UUID, token string, expiresAt time.Time, userAgent, ipAddress *string) (*models.Session, error)
-    GetSessionByToken(ctx context.Context, token string) (*models.Session, error)
-    DeleteSession(ctx context.Context, token string) error
-    CleanupExpiredSessions(ctx context.Context) error
-    
-    // Share operations
-    CreateDocumentShare(ctx context.Context, documentID, userID uuid.UUID, permission string, createdBy *uuid.UUID) (*models.DocumentShare, bool, error)
-    ListDocumentShares(ctx context.Context, documentID uuid.UUID) ([]models.DocumentShareWithUser, error)
-    DeleteDocumentShare(ctx context.Context, documentID, userID uuid.UUID) error
-    CanViewDocument(ctx context.Context, documentID, userID uuid.UUID) (bool, error)
-    CanEditDocument(ctx context.Context, documentID, userID uuid.UUID) (bool, error)
-    IsDocumentOwner(ctx context.Context, documentID, userID uuid.UUID) (bool, error)
+	// Document operations
+	CreateDocument(name string, docType models.DocumentType) (*models.Document, error)
+	CreateDocumentWithOwner(name string, docType models.DocumentType, ownerID *uuid.UUID) (*models.Document, error) // ADD THIS
+	GetDocument(id uuid.UUID) (*models.Document, error)
+	ListDocuments() ([]models.Document, error)
+	ListUserDocuments(ctx context.Context, userID uuid.UUID) ([]models.Document, error) // ADD THIS
+	UpdateDocumentState(id uuid.UUID, state []byte) error
+	DeleteDocument(id uuid.UUID) error
+
+	// User operations
+	UpsertUser(ctx context.Context, provider, providerUserID, email, name string, avatarURL *string) (*models.User, error)
+	GetUserByID(ctx context.Context, userID uuid.UUID) (*models.User, error)
+	GetUserByEmail(ctx context.Context, email string) (*models.User, error)
+
+	// Session operations
+	CreateSession(ctx context.Context, userID uuid.UUID, sessionID uuid.UUID, token string, expiresAt time.Time, userAgent, ipAddress *string) (*models.Session, error)
+	GetSessionByToken(ctx context.Context, token string) (*models.Session, error)
+	DeleteSession(ctx context.Context, token string) error
+	CleanupExpiredSessions(ctx context.Context) error
+
+	// Share operations
+	CreateDocumentShare(ctx context.Context, documentID, userID uuid.UUID, permission string, createdBy *uuid.UUID) (*models.DocumentShare, bool, error)
+	ListDocumentShares(ctx context.Context, documentID uuid.UUID) ([]models.DocumentShareWithUser, error)
+	DeleteDocumentShare(ctx context.Context, documentID, userID uuid.UUID) error
+	CanViewDocument(ctx context.Context, documentID, userID uuid.UUID) (bool, error)
+	CanEditDocument(ctx context.Context, documentID, userID uuid.UUID) (bool, error)
+	IsDocumentOwner(ctx context.Context, documentID, userID uuid.UUID) (bool, error)
 	GenerateShareToken(ctx context.Context, documentID uuid.UUID, permission string) (string, error)
 	ValidateShareToken(ctx context.Context, documentID uuid.UUID, token string) (bool, error)
 	RevokeShareToken(ctx context.Context, documentID uuid.UUID) error
@@ -53,13 +53,11 @@ type Store interface {
 	GetDocumentVersion(ctx context.Context, versionID uuid.UUID) (*models.DocumentVersion, error)
 	GetLatestDocumentVersion(ctx context.Context, documentID uuid.UUID) (*models.DocumentVersion, error)
 
-
-    Close() error
+	Close() error
 }
 
-
 type PostgresStore struct {
-    db *sql.DB
+	db *sql.DB
 }
 
 func NewPostgresStore(databaseUrl string) (*PostgresStore, error) {
@@ -68,17 +66,17 @@ func NewPostgresStore(databaseUrl string) (*PostgresStore, error) {
 		return nil, error
 	}
 	if err := db.Ping(); err != nil {
-  		return nil, fmt.Errorf("failed to ping database: %w", err)
-  	}
+		return nil, fmt.Errorf("failed to ping database: %w", err)
+	}
 	db.SetMaxOpenConns(25)
-  	db.SetMaxIdleConns(5)
-  	db.SetConnMaxLifetime(5 * time.Minute)
+	db.SetMaxIdleConns(5)
+	db.SetConnMaxLifetime(5 * time.Minute)
 	return &PostgresStore{db: db}, nil
 }
 
 func (s *PostgresStore) Close() error {
-  	return s.db.Close()
-  }
+	return s.db.Close()
+}
 
 func (s *PostgresStore) CreateDocument(name string, docType models.DocumentType) (*models.Document, error) {
 	doc := &models.Document{
@@ -95,12 +93,11 @@ func (s *PostgresStore) CreateDocument(name string, docType models.DocumentType)
   		RETURNING id, name, type, created_at, updated_at
 	`
 	err := s.db.QueryRow(query,
-		doc.ID, 
-		doc.Name, 
-		doc.Type, 
-		doc.CreatedAt, 
+		doc.ID,
+		doc.Name,
+		doc.Type,
+		doc.CreatedAt,
 		doc.UpdatedAt,
-
 	).Scan(&doc.ID, &doc.Name, &doc.Type, &doc.CreatedAt, &doc.UpdatedAt)
 
 	if err != nil {
@@ -109,164 +106,163 @@ func (s *PostgresStore) CreateDocument(name string, docType models.DocumentType)
 	return doc, nil
 }
 
- // GetDocument retrieves a document by ID
-  func (s *PostgresStore) GetDocument(id uuid.UUID) (*models.Document, error) {
-  	doc := &models.Document{}
+// GetDocument retrieves a document by ID
+func (s *PostgresStore) GetDocument(id uuid.UUID) (*models.Document, error) {
+	doc := &models.Document{}
 
-  	query := `
+	query := `
   		SELECT id, name, type, yjs_state, owner_id, is_public, created_at, updated_at
   		FROM documents
   		WHERE id = $1
   	`
 
-  	err := s.db.QueryRow(query, id).Scan(
-  		&doc.ID,
-  		&doc.Name,
-  		&doc.Type,
-  		&doc.YjsState,
-  		&doc.OwnerID,
-  		&doc.Is_Public,
-  		&doc.CreatedAt,
-  		&doc.UpdatedAt,
-  	)
+	err := s.db.QueryRow(query, id).Scan(
+		&doc.ID,
+		&doc.Name,
+		&doc.Type,
+		&doc.YjsState,
+		&doc.OwnerID,
+		&doc.Is_Public,
+		&doc.CreatedAt,
+		&doc.UpdatedAt,
+	)
 
-  	if err == sql.ErrNoRows {
-  		return nil, fmt.Errorf("document not found")
-  	}
-  	if err != nil {
-  		return nil, fmt.Errorf("failed to get document: %w", err)
-  	}
+	if err == sql.ErrNoRows {
+		return nil, fmt.Errorf("document not found")
+	}
+	if err != nil {
+		return nil, fmt.Errorf("failed to get document: %w", err)
+	}
 
-  	return doc, nil
-  }
+	return doc, nil
+}
 
-
- // ListDocuments retrieves all documents
- func (s *PostgresStore) ListDocuments() ([]models.Document, error) {
-  	query := `
+// ListDocuments retrieves all documents
+func (s *PostgresStore) ListDocuments() ([]models.Document, error) {
+	query := `
   		SELECT id, name, type, created_at, updated_at
   		FROM documents
   		ORDER BY created_at DESC
   	`
 
-  	rows, err := s.db.Query(query)
-  	if err != nil {
-  		return nil, fmt.Errorf("failed to list documents: %w", err)
-  	}
-  	defer rows.Close()
+	rows, err := s.db.Query(query)
+	if err != nil {
+		return nil, fmt.Errorf("failed to list documents: %w", err)
+	}
+	defer rows.Close()
 
-  	var documents []models.Document
-  	for rows.Next() {
-  		var doc models.Document
-  		err := rows.Scan(&doc.ID, &doc.Name, &doc.Type, &doc.CreatedAt, &doc.UpdatedAt)
-  		if err != nil {
-  			return nil, fmt.Errorf("failed to scan document: %w", err)
-  		}
-  		documents = append(documents, doc)
-  	}
+	var documents []models.Document
+	for rows.Next() {
+		var doc models.Document
+		err := rows.Scan(&doc.ID, &doc.Name, &doc.Type, &doc.CreatedAt, &doc.UpdatedAt)
+		if err != nil {
+			return nil, fmt.Errorf("failed to scan document: %w", err)
+		}
+		documents = append(documents, doc)
+	}
 
-  	return documents, nil
-  }
+	return documents, nil
+}
 
- func (s *PostgresStore) UpdateDocumentState(id uuid.UUID, state []byte) error {
-  	query := `
+func (s *PostgresStore) UpdateDocumentState(id uuid.UUID, state []byte) error {
+	query := `
   		UPDATE documents
   		SET yjs_state = $1, updated_at = $2
   		WHERE id = $3
   	`
 
-  	result, err := s.db.Exec(query, state, time.Now(), id)
-  	if err != nil {
-  		return fmt.Errorf("failed to update document state: %w", err)
-  	}
+	result, err := s.db.Exec(query, state, time.Now(), id)
+	if err != nil {
+		return fmt.Errorf("failed to update document state: %w", err)
+	}
 
-  	rowsAffected, err := result.RowsAffected()
-  	if err != nil {
-  		return fmt.Errorf("failed to get rows affected: %w", err)
-  	}
+	rowsAffected, err := result.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("failed to get rows affected: %w", err)
+	}
 
-  	if rowsAffected == 0 {
-  		return fmt.Errorf("document not found")
-  	}
+	if rowsAffected == 0 {
+		return fmt.Errorf("document not found")
+	}
 
-  	return nil
-  }
+	return nil
+}
 
- func (s *PostgresStore) DeleteDocument(id uuid.UUID) error {
-  	query := `DELETE FROM documents WHERE id = $1`
+func (s *PostgresStore) DeleteDocument(id uuid.UUID) error {
+	query := `DELETE FROM documents WHERE id = $1`
 
-  	result, err := s.db.Exec(query, id)
-  	if err != nil {
-  		return fmt.Errorf("failed to delete document: %w", err)
-  	}
+	result, err := s.db.Exec(query, id)
+	if err != nil {
+		return fmt.Errorf("failed to delete document: %w", err)
+	}
 
-  	rowsAffected, err := result.RowsAffected()
-  	if err != nil {
-  		return fmt.Errorf("failed to get rows affected: %w", err)
-  	}
+	rowsAffected, err := result.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("failed to get rows affected: %w", err)
+	}
 
-  	if rowsAffected == 0 {
-  		return fmt.Errorf("document not found")
-  	}
+	if rowsAffected == 0 {
+		return fmt.Errorf("document not found")
+	}
 
-  	return nil
-  }
+	return nil
+}
 
 // CreateDocumentWithOwner creates a new document with owner
 func (s *PostgresStore) CreateDocumentWithOwner(name string, docType models.DocumentType, ownerID *uuid.UUID) (*models.Document, error) {
-    // 1. 检查 docType 是否为空，或者是否合法 (防止 check constraint 报错)
-    if docType == "" {
-        docType = models.DocumentTypeEditor // Default to editor instead of invalid "text"
-    }
+	// 1. 检查 docType 是否为空，或者是否合法 (防止 check constraint 报错)
+	if docType == "" {
+		docType = models.DocumentTypeEditor // Default to editor instead of invalid "text"
+	}
 
-    // Validate that docType is one of the allowed values
-    if docType != models.DocumentTypeEditor && docType != models.DocumentTypeKanban {
-        return nil, fmt.Errorf("invalid document type: %s (must be 'editor' or 'kanban')", docType)
-    }
+	// Validate that docType is one of the allowed values
+	if docType != models.DocumentTypeEditor && docType != models.DocumentTypeKanban {
+		return nil, fmt.Errorf("invalid document type: %s (must be 'editor' or 'kanban')", docType)
+	}
 
-    doc := &models.Document{
-        ID:        uuid.New(),
-        Name:      name,
-        Type:      docType,
-        YjsState:  []byte{}, // 这里初始化了空字节
-        OwnerID:   ownerID,
-        Is_Public:  false,    // 显式设置默认值
-        CreatedAt: time.Now(),
-        UpdatedAt: time.Now(),
-    }
+	doc := &models.Document{
+		ID:        uuid.New(),
+		Name:      name,
+		Type:      docType,
+		YjsState:  []byte{}, // 这里初始化了空字节
+		OwnerID:   ownerID,
+		Is_Public: false, // 显式设置默认值
+		CreatedAt: time.Now(),
+		UpdatedAt: time.Now(),
+	}
 
-    // 2. 补全了 yjs_state 和 is_public
-    query := `
+	// 2. 补全了 yjs_state 和 is_public
+	query := `
         INSERT INTO documents (id, name, type, owner_id, yjs_state, is_public, created_at, updated_at)
         VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
         RETURNING id, name, type, owner_id, yjs_state, is_public, created_at, updated_at
     `
-    
-    // 3. Scan 的时候也要对应加上
-    err := s.db.QueryRow(query,
-        doc.ID,
-        doc.Name,
-        doc.Type,
-        doc.OwnerID,
-        doc.YjsState, // $5
-        doc.Is_Public, // $6
-        doc.CreatedAt,
-        doc.UpdatedAt,
-    ).Scan(
-        &doc.ID, 
-        &doc.Name, 
-        &doc.Type, 
-        &doc.OwnerID, 
-        &doc.YjsState, // Scan 回来
-        &doc.Is_Public, // Scan 回来
-        &doc.CreatedAt, 
-        &doc.UpdatedAt,
-    )
 
-    if err != nil {
-        return nil, fmt.Errorf("failed to create document: %w", err)
-    }
-    return doc, nil
+	// 3. Scan 的时候也要对应加上
+	err := s.db.QueryRow(query,
+		doc.ID,
+		doc.Name,
+		doc.Type,
+		doc.OwnerID,
+		doc.YjsState,  // $5
+		doc.Is_Public, // $6
+		doc.CreatedAt,
+		doc.UpdatedAt,
+	).Scan(
+		&doc.ID,
+		&doc.Name,
+		&doc.Type,
+		&doc.OwnerID,
+		&doc.YjsState,  // Scan 回来
+		&doc.Is_Public, // Scan 回来
+		&doc.CreatedAt,
+		&doc.UpdatedAt,
+	)
+
+	if err != nil {
+		return nil, fmt.Errorf("failed to create document: %w", err)
+	}
+	return doc, nil
 }
 
 // ListUserDocuments lists documents owned by or shared with a user
diff --git a/backend/internal/store/session.go b/backend/internal/store/session.go
index 4e21686..b1852ce 100644
--- a/backend/internal/store/session.go
+++ b/backend/internal/store/session.go
@@ -12,77 +12,77 @@ import (
 
 // CreateSession creates a new session
 func (s *PostgresStore) CreateSession(ctx context.Context, userID uuid.UUID, sessionID uuid.UUID, token string, expiresAt time.Time, userAgent, ipAddress *string) (*models.Session, error) {
-    // Hash the token before storing
-    hash := sha256.Sum256([]byte(token))
-    tokenHash := hex.EncodeToString(hash[:])
+	// Hash the token before storing
+	hash := sha256.Sum256([]byte(token))
+	tokenHash := hex.EncodeToString(hash[:])
 
-    // 【修改点 1】: 在 SQL 里显式加上 id 字段
-    // 注意：$1 变成了 id，后面的参数序号全部要顺延 (+1)
-    query := `         
+	// 【修改点 1】: 在 SQL 里显式加上 id 字段
+	// 注意：$1 变成了 id，后面的参数序号全部要顺延 (+1)
+	query := `         
         INSERT INTO sessions (id, user_id, token_hash, expires_at, user_agent, ip_address)
         VALUES ($1, $2, $3, $4, $5, $6)
         RETURNING id, user_id, token_hash, expires_at, created_at, user_agent, ip_address
     `
 
-    var session models.Session
-    // 【修改点 2】: 在参数列表的最前面加上 sessionID
-    // 现在的对应关系：
-    // $1 -> sessionID
-    // $2 -> userID
-    // $3 -> tokenHash
-    // ...
-    err := s.db.QueryRowContext(ctx, query, 
-        sessionID, // <--- 这里！把它传进去！
-        userID, 
-        tokenHash, 
-        expiresAt, 
-        userAgent, 
-        ipAddress,
-    ).Scan(
-        &session.ID, &session.UserID, &session.TokenHash, &session.ExpiresAt,
-        &session.CreatedAt, &session.UserAgent, &session.IPAddress,
-    )
-    if err != nil {
-        return nil, err
-    }
+	var session models.Session
+	// 【修改点 2】: 在参数列表的最前面加上 sessionID
+	// 现在的对应关系：
+	// $1 -> sessionID
+	// $2 -> userID
+	// $3 -> tokenHash
+	// ...
+	err := s.db.QueryRowContext(ctx, query,
+		sessionID, // <--- 这里！把它传进去！
+		userID,
+		tokenHash,
+		expiresAt,
+		userAgent,
+		ipAddress,
+	).Scan(
+		&session.ID, &session.UserID, &session.TokenHash, &session.ExpiresAt,
+		&session.CreatedAt, &session.UserAgent, &session.IPAddress,
+	)
+	if err != nil {
+		return nil, err
+	}
 
-    return &session, nil
+	return &session, nil
 }
 
 // GetSessionByToken retrieves session by JWT token
 func (s *PostgresStore) GetSessionByToken(ctx context.Context, token string) (*models.Session, error) {
-    hash := sha256.Sum256([]byte(token))
-    tokenHash := hex.EncodeToString(hash[:])
+	hash := sha256.Sum256([]byte(token))
+	tokenHash := hex.EncodeToString(hash[:])
 
-    query := `
+	query := `
         SELECT id, user_id, token_hash, expires_at, created_at, user_agent, ip_address
         FROM sessions
         WHERE token_hash = $1 AND expires_at > NOW()
     `
 
-    var session models.Session
-    err := s.db.QueryRowContext(ctx, query, tokenHash).Scan(
-        &session.ID, &session.UserID, &session.TokenHash, &session.ExpiresAt,
-        &session.CreatedAt, &session.UserAgent, &session.IPAddress,
-    )
-    if err != nil {
-        return nil, err
-    }
+	var session models.Session
+	err := s.db.QueryRowContext(ctx, query, tokenHash).Scan(
+		&session.ID, &session.UserID, &session.TokenHash, &session.ExpiresAt,
+		&session.CreatedAt, &session.UserAgent, &session.IPAddress,
+	)
+	if err != nil {
+		return nil, err
+	}
 
-    return &session, nil
+	return &session, nil
 }
 
 // DeleteSession deletes a session (logout)
 func (s *PostgresStore) DeleteSession(ctx context.Context, token string) error {
-    hash := sha256.Sum256([]byte(token))
-    tokenHash := hex.EncodeToString(hash[:])
+	hash := sha256.Sum256([]byte(token))
+	tokenHash := hex.EncodeToString(hash[:])
 
-    _, err := s.db.ExecContext(ctx, "DELETE FROM sessions WHERE token_hash = $1", tokenHash)
-    return err
+	_, err := s.db.ExecContext(ctx, "DELETE FROM sessions WHERE token_hash = $1", tokenHash)
+	return err
 }
 
 // CleanupExpiredSessions removes expired sessions
 func (s *PostgresStore) CleanupExpiredSessions(ctx context.Context) error {
-    _, err := s.db.ExecContext(ctx, "DELETE FROM sessions WHERE expires_at < NOW()")
-    return err
+	_, err := s.db.ExecContext(ctx, "DELETE FROM sessions WHERE expires_at < NOW()")
+	return err
 }
diff --git a/backend/internal/store/share.go b/backend/internal/store/share.go
index c921425..2346f95 100644
--- a/backend/internal/store/share.go
+++ b/backend/internal/store/share.go
@@ -14,34 +14,34 @@ import (
 // CreateDocumentShare creates a new share or updates existing one
 // Returns the share and a boolean indicating if it was newly created (true) or updated (false)
 func (s *PostgresStore) CreateDocumentShare(ctx context.Context, documentID, userID uuid.UUID, permission string, createdBy *uuid.UUID) (*models.DocumentShare, bool, error) {
-    // First check if share already exists
-    var existingID uuid.UUID
-    checkQuery := `SELECT id FROM document_shares WHERE document_id = $1 AND user_id = $2`
-    err := s.db.QueryRowContext(ctx, checkQuery, documentID, userID).Scan(&existingID)
-    isNewShare := err != nil // If error (not found), it's a new share
+	// First check if share already exists
+	var existingID uuid.UUID
+	checkQuery := `SELECT id FROM document_shares WHERE document_id = $1 AND user_id = $2`
+	err := s.db.QueryRowContext(ctx, checkQuery, documentID, userID).Scan(&existingID)
+	isNewShare := err != nil // If error (not found), it's a new share
 
-    query := `
+	query := `
         INSERT INTO document_shares (document_id, user_id, permission, created_by)
         VALUES ($1, $2, $3, $4)
         ON CONFLICT (document_id, user_id) DO UPDATE SET permission = EXCLUDED.permission
         RETURNING id, document_id, user_id, permission, created_at, created_by
     `
 
-    var share models.DocumentShare
-    err = s.db.QueryRowContext(ctx, query, documentID, userID, permission, createdBy).Scan(
-        &share.ID, &share.DocumentID, &share.UserID, &share.Permission,
-        &share.CreatedAt, &share.CreatedBy,
-    )
-    if err != nil {
-        return nil, false, err
-    }
+	var share models.DocumentShare
+	err = s.db.QueryRowContext(ctx, query, documentID, userID, permission, createdBy).Scan(
+		&share.ID, &share.DocumentID, &share.UserID, &share.Permission,
+		&share.CreatedAt, &share.CreatedBy,
+	)
+	if err != nil {
+		return nil, false, err
+	}
 
-    return &share, isNewShare, nil
+	return &share, isNewShare, nil
 }
 
 // ListDocumentShares lists all shares for a document
 func (s *PostgresStore) ListDocumentShares(ctx context.Context, documentID uuid.UUID) ([]models.DocumentShareWithUser, error) {
-    query := `
+	query := `
         SELECT
             ds.id, ds.document_id, ds.user_id, ds.permission, ds.created_at, ds.created_by,
             u.id, u.email, u.name, u.avatar_url, u.provider, u.provider_user_id, u.created_at, u.updated_at, u.last_login_at
@@ -51,38 +51,38 @@ func (s *PostgresStore) ListDocumentShares(ctx context.Context, documentID uuid.
         ORDER BY ds.created_at DESC
     `
 
-    rows, err := s.db.QueryContext(ctx, query, documentID)
-    if err != nil {
-        return nil, err
-    }
-    defer rows.Close()
+	rows, err := s.db.QueryContext(ctx, query, documentID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
 
-    var shares []models.DocumentShareWithUser
-    for rows.Next() {
-        var share models.DocumentShareWithUser
-        err := rows.Scan(
-            &share.ID, &share.DocumentID, &share.UserID, &share.Permission, &share.CreatedAt, &share.CreatedBy,
-            &share.User.ID, &share.User.Email, &share.User.Name, &share.User.AvatarURL, &share.User.Provider,
-            &share.User.ProviderUserID, &share.User.CreatedAt, &share.User.UpdatedAt, &share.User.LastLoginAt,
-        )
-        if err != nil {
-            return nil, err
-        }
-        shares = append(shares, share)
-    }
+	var shares []models.DocumentShareWithUser
+	for rows.Next() {
+		var share models.DocumentShareWithUser
+		err := rows.Scan(
+			&share.ID, &share.DocumentID, &share.UserID, &share.Permission, &share.CreatedAt, &share.CreatedBy,
+			&share.User.ID, &share.User.Email, &share.User.Name, &share.User.AvatarURL, &share.User.Provider,
+			&share.User.ProviderUserID, &share.User.CreatedAt, &share.User.UpdatedAt, &share.User.LastLoginAt,
+		)
+		if err != nil {
+			return nil, err
+		}
+		shares = append(shares, share)
+	}
 
-    return shares, nil
+	return shares, nil
 }
 
 // DeleteDocumentShare deletes a share
 func (s *PostgresStore) DeleteDocumentShare(ctx context.Context, documentID, userID uuid.UUID) error {
-    _, err := s.db.ExecContext(ctx, "DELETE FROM document_shares WHERE document_id = $1 AND user_id = $2", documentID, userID)
-    return err
+	_, err := s.db.ExecContext(ctx, "DELETE FROM document_shares WHERE document_id = $1 AND user_id = $2", documentID, userID)
+	return err
 }
 
 // CanViewDocument checks if user can view document (owner OR has any share)
 func (s *PostgresStore) CanViewDocument(ctx context.Context, documentID, userID uuid.UUID) (bool, error) {
-    query := `
+	query := `
         SELECT EXISTS(
             SELECT 1 FROM documents WHERE id = $1 AND owner_id = $2
             UNION
@@ -90,14 +90,14 @@ func (s *PostgresStore) CanViewDocument(ctx context.Context, documentID, userID
         )
     `
 
-    var canView bool
-    err := s.db.QueryRowContext(ctx, query, documentID, userID).Scan(&canView)
-    return canView, err
+	var canView bool
+	err := s.db.QueryRowContext(ctx, query, documentID, userID).Scan(&canView)
+	return canView, err
 }
 
 // CanEditDocument checks if user can edit document (owner OR has edit share)
 func (s *PostgresStore) CanEditDocument(ctx context.Context, documentID, userID uuid.UUID) (bool, error) {
-    query := `
+	query := `
         SELECT EXISTS(
             SELECT 1 FROM documents WHERE id = $1 AND owner_id = $2
             UNION
@@ -105,21 +105,21 @@ func (s *PostgresStore) CanEditDocument(ctx context.Context, documentID, userID
         )
     `
 
-    var canEdit bool
-    err := s.db.QueryRowContext(ctx, query, documentID, userID).Scan(&canEdit)
-    return canEdit, err
+	var canEdit bool
+	err := s.db.QueryRowContext(ctx, query, documentID, userID).Scan(&canEdit)
+	return canEdit, err
 }
 
 // IsDocumentOwner checks if user is the owner
 func (s *PostgresStore) IsDocumentOwner(ctx context.Context, documentID, userID uuid.UUID) (bool, error) {
-    query := `SELECT owner_id = $2 FROM documents WHERE id = $1`
+	query := `SELECT owner_id = $2 FROM documents WHERE id = $1`
 
-    var isOwner bool
-    err := s.db.QueryRowContext(ctx, query, documentID, userID).Scan(&isOwner)
-    if err == sql.ErrNoRows {
-        return false, nil
-    }
-    return isOwner, err
+	var isOwner bool
+	err := s.db.QueryRowContext(ctx, query, documentID, userID).Scan(&isOwner)
+	if err == sql.ErrNoRows {
+		return false, nil
+	}
+	return isOwner, err
 }
 func (s *PostgresStore) GenerateShareToken(ctx context.Context, documentID uuid.UUID, permission string) (string, error) {
 	// Generate random 32-byte token
@@ -239,4 +239,4 @@ func (s *PostgresStore) GetShareLinkPermission(ctx context.Context, documentID u
 	}
 
 	return permission, nil
-}
\ No newline at end of file
+}
diff --git a/backend/internal/store/user.go b/backend/internal/store/user.go
index 18e7fd4..79fd964 100644
--- a/backend/internal/store/user.go
+++ b/backend/internal/store/user.go
@@ -11,7 +11,7 @@ import (
 
 // UpsertUser creates or updates user from OAuth profile
 func (s *PostgresStore) UpsertUser(ctx context.Context, provider, providerUserID, email, name string, avatarURL *string) (*models.User, error) {
-    query := `
+	query := `
         INSERT INTO users (provider, provider_user_id, email, name, avatar_url, last_login_at)
         VALUES ($1, $2, $3, $4, $5, NOW())
         ON CONFLICT (provider, provider_user_id)
@@ -24,59 +24,59 @@ func (s *PostgresStore) UpsertUser(ctx context.Context, provider, providerUserID
         RETURNING id, email, name, avatar_url, provider, provider_user_id, created_at, updated_at, last_login_at
     `
 
-    var user models.User
-    err := s.db.QueryRowContext(ctx, query, provider, providerUserID, email, name, avatarURL).Scan(
-        &user.ID, &user.Email, &user.Name, &user.AvatarURL, &user.Provider,
-        &user.ProviderUserID, &user.CreatedAt, &user.UpdatedAt, &user.LastLoginAt,
-    )
-    if err != nil {
-        return nil, err
-    }
-    fmt.Printf("✅ User Upserted: ID=%s, Email=%s\n", user.ID.String(), user.Email)
+	var user models.User
+	err := s.db.QueryRowContext(ctx, query, provider, providerUserID, email, name, avatarURL).Scan(
+		&user.ID, &user.Email, &user.Name, &user.AvatarURL, &user.Provider,
+		&user.ProviderUserID, &user.CreatedAt, &user.UpdatedAt, &user.LastLoginAt,
+	)
+	if err != nil {
+		return nil, err
+	}
+	fmt.Printf("✅ User Upserted: ID=%s, Email=%s\n", user.ID.String(), user.Email)
 
-    return &user, nil
+	return &user, nil
 }
 
 // GetUserByID retrieves user by ID
 func (s *PostgresStore) GetUserByID(ctx context.Context, userID uuid.UUID) (*models.User, error) {
-    query := `
+	query := `
         SELECT id, email, name, avatar_url, provider, provider_user_id, created_at, updated_at, last_login_at
         FROM users WHERE id = $1
     `
 
-    var user models.User
-    err := s.db.QueryRowContext(ctx, query, userID).Scan(
-        &user.ID, &user.Email, &user.Name, &user.AvatarURL, &user.Provider,
-        &user.ProviderUserID, &user.CreatedAt, &user.UpdatedAt, &user.LastLoginAt,
-    )
-    if err == sql.ErrNoRows {
-        return nil, nil
-    }
-    if err != nil {
-        return nil, err
-    }
+	var user models.User
+	err := s.db.QueryRowContext(ctx, query, userID).Scan(
+		&user.ID, &user.Email, &user.Name, &user.AvatarURL, &user.Provider,
+		&user.ProviderUserID, &user.CreatedAt, &user.UpdatedAt, &user.LastLoginAt,
+	)
+	if err == sql.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
 
-    return &user, nil
+	return &user, nil
 }
 
 // GetUserByEmail retrieves user by email
 func (s *PostgresStore) GetUserByEmail(ctx context.Context, email string) (*models.User, error) {
-    query := `
+	query := `
         SELECT id, email, name, avatar_url, provider, provider_user_id, created_at, updated_at, last_login_at
         FROM users WHERE email = $1
     `
 
-    var user models.User
-    err := s.db.QueryRowContext(ctx, query, email).Scan(
-        &user.ID, &user.Email, &user.Name, &user.AvatarURL, &user.Provider,
-        &user.ProviderUserID, &user.CreatedAt, &user.UpdatedAt, &user.LastLoginAt,
-    )
-    if err == sql.ErrNoRows {
-        return nil, nil
-    }
-    if err != nil {
-        return nil, err
-    }
+	var user models.User
+	err := s.db.QueryRowContext(ctx, query, email).Scan(
+		&user.ID, &user.Email, &user.Name, &user.AvatarURL, &user.Provider,
+		&user.ProviderUserID, &user.CreatedAt, &user.UpdatedAt, &user.LastLoginAt,
+	)
+	if err == sql.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
 
-    return &user, nil
+	return &user, nil
 }