Refactor and improve code consistency across multiple files

- Enhanced SQL queries in `session.go` and `share.go` for clarity and consistency.
- Updated comments for better understanding and maintenance.
- Ensured consistent error handling and return statements across various methods.

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,
+	}
 }