fix: detect and clear stale IndexedDB auth tokens (refs #190)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/core/auth/Auth0Provider.tsx

@@ -57,8 +57,9 @@ export const Auth0Provider: React.FC<Auth0ProviderProps> = ({ children }) => {
 
 // Component to inject token into API client with mobile support
 const TokenInjector: React.FC<{ children: React.ReactNode }> = ({ children }) => {
-  const { getAccessTokenSilently, isAuthenticated, isLoading, user } = useAuth0();
+  const { getAccessTokenSilently, isAuthenticated, isLoading, user, logout } = useAuth0();
   const [retryCount, setRetryCount] = React.useState(0);
+  const validatingRef = React.useRef(false);
 
   // Basic component loading debug
   console.log('[TokenInjector] Component loaded');
@@ -116,6 +117,31 @@ const TokenInjector: React.FC<{ children: React.ReactNode }> = ({ children }) =>
     return null;
   };
 
+  // Prevent stale session state when cached token is no longer valid
+  React.useEffect(() => {
+    if (!isAuthenticated || isLoading || validatingRef.current) return;
+
+    const validateToken = async () => {
+      validatingRef.current = true;
+      try {
+        await getAccessTokenSilently({ cacheMode: 'off', timeoutInSeconds: 10 });
+      } catch (error: any) {
+        const errorType = error?.error || error?.message || '';
+        if (errorType.includes('login_required') || errorType.includes('consent_required') ||
+            errorType.includes('invalid_grant')) {
+          console.warn('[Auth] Stale token detected, clearing auth state');
+          const { indexedDBStorage } = await import('../utils/indexeddb-storage');
+          await indexedDBStorage.clearAll();
+          logout({ openUrl: false });
+          return;
+        }
+      }
+      validatingRef.current = false;
+    };
+
+    validateToken();
+  }, [isAuthenticated, isLoading]);
+
   // Force authentication check for devices when user seems logged in but isAuthenticated is false
   React.useEffect(() => {
     const isMobile = /Android|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent);

frontend/src/core/utils/indexeddb-storage.ts

@@ -157,6 +157,23 @@ class IndexedDBStorage implements StorageAdapter, Auth0Cache {
     }
   }
 
+  async clearAll(): Promise<void> {
+    await this.initPromise;
+    if (!this.db) {
+      this.memoryCache.clear();
+      return;
+    }
+    const tx = this.db.transaction(this.storeName, 'readwrite');
+    tx.objectStore(this.storeName).clear();
+    await new Promise<void>((resolve, reject) => {
+      tx.oncomplete = () => {
+        this.memoryCache.clear();
+        resolve();
+      };
+      tx.onerror = () => reject(tx.error);
+    });
+  }
+
   key(index: number): string | null {
     const keys = Array.from(this.memoryCache.keys());
     return keys[index] || null;