feat: add guest mode, bug fixes, and self-hosted config

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

frontend/src/contexts/AuthContext.tsx

@@ -1,4 +1,4 @@
-import { createContext, useContext, useState, useEffect } from 'react';
+import { createContext, useContext, useState, useEffect, useCallback } from 'react';
 import type { ReactNode } from 'react';
 import type { User, AuthContextType } from '../types/auth';
 import { authApi } from '../api/auth';
@@ -40,7 +40,7 @@ export function AuthProvider({ children }: { children: ReactNode }) {
     initAuth();
   }, []);
 
-  const login = async (newToken: string) => {
+  const login = useCallback(async (newToken: string) => {
     try {
       setLoading(true);
       setError(null);
@@ -60,7 +60,7 @@ export function AuthProvider({ children }: { children: ReactNode }) {
     } finally {
       setLoading(false);
     }
-  };
+  }, []);
 
   const logout = () => {
     localStorage.removeItem('auth_token');