feat(auth): implement auto guest mode and enhance token system

- Add role-based token system with metadata support
- Implement automatic guest mode for unconfigured authentication
- Create new /auth-status endpoint for authentication status checking
- Modify frontend to auto-detect auth status and bypass login when appropriate
- Add guest mode indicator in site header for better UX

This change allows users to automatically access the system without manual
login when authentication is not configured, while maintaining secure
authentication when credentials are properly set up.

lightrag_webui/src/stores/state.ts

@@ -19,7 +19,8 @@ interface BackendState {
 interface AuthState {
   isAuthenticated: boolean;
   showLoginModal: boolean;
-  login: (token: string) => void;
+  isGuestMode: boolean;  // Add guest mode flag
+  login: (token: string, isGuest?: boolean) => void;
   logout: () => void;
   setShowLoginModal: (show: boolean) => void;
 }
@@ -66,16 +67,63 @@ const useBackendState = createSelectors(useBackendStateStoreBase)
 
 export { useBackendState }
 
-export const useAuthStore = create<AuthState>(set => ({
-  isAuthenticated: !!localStorage.getItem('LIGHTRAG-API-TOKEN'),
-  showLoginModal: false,
-  login: (token) => {
-    localStorage.setItem('LIGHTRAG-API-TOKEN', token);
-    set({ isAuthenticated: true, showLoginModal: false });
-  },
-  logout: () => {
-    localStorage.removeItem('LIGHTRAG-API-TOKEN');
-    set({ isAuthenticated: false });
-  },
-  setShowLoginModal: (show) => set({ showLoginModal: show })
-}));
+// Helper function to check if token is a guest token
+const isGuestToken = (token: string): boolean => {
+  try {
+    // JWT tokens are in the format: header.payload.signature
+    const parts = token.split('.');
+    if (parts.length !== 3) return false;
+    
+    // Decode the payload (second part)
+    const payload = JSON.parse(atob(parts[1]));
+    
+    // Check if the token has a role field with value "guest"
+    return payload.role === 'guest';
+  } catch (e) {
+    console.error('Error parsing token:', e);
+    return false;
+  }
+};
+
+// Initialize auth state from localStorage
+const initAuthState = (): { isAuthenticated: boolean; isGuestMode: boolean } => {
+  const token = localStorage.getItem('LIGHTRAG-API-TOKEN');
+  if (!token) {
+    return { isAuthenticated: false, isGuestMode: false };
+  }
+  
+  return { 
+    isAuthenticated: true, 
+    isGuestMode: isGuestToken(token)
+  };
+};
+
+export const useAuthStore = create<AuthState>(set => {
+  // Get initial state from localStorage
+  const initialState = initAuthState();
+  
+  return {
+    isAuthenticated: initialState.isAuthenticated,
+    showLoginModal: false,
+    isGuestMode: initialState.isGuestMode,
+    
+    login: (token, isGuest = false) => {
+      localStorage.setItem('LIGHTRAG-API-TOKEN', token);
+      set({ 
+        isAuthenticated: true, 
+        showLoginModal: false,
+        isGuestMode: isGuest
+      });
+    },
+    
+    logout: () => {
+      localStorage.removeItem('LIGHTRAG-API-TOKEN');
+      set({ 
+        isAuthenticated: false,
+        isGuestMode: false
+      });
+    },
+    
+    setShowLoginModal: (show) => set({ showLoginModal: show })
+  };
+});