Revert Zustand persist middleware approach and restore AuthInitializer

- Remove persist middleware from authStore (causing hooks timing issues)
- Restore original AuthInitializer component pattern
- Keep good Phase 3 optimizations:
  - Theme FOUC fix (inline script)
  - React Query refetchOnWindowFocus disabled
  - Code splitting for dev/auth components
  - Shared form components (FormField, useFormError)
  - Store location in lib/stores

frontend/src/components/auth/AuthGuard.tsx

@@ -63,16 +63,11 @@ function LoadingSpinner() {
 export function AuthGuard({ children, requireAdmin = false, fallback }: AuthGuardProps) {
   const router = useRouter();
   const pathname = usePathname();
-  const { isAuthenticated, isLoading: authLoading, user, _hasHydrated } = useAuthStore();
+  const { isAuthenticated, isLoading: authLoading, user } = useAuthStore();
 
   // Fetch user data if authenticated but user not loaded
   const { isLoading: userLoading } = useMe();
 
-  // Wait for store to hydrate from localStorage to prevent hook order issues
-  if (!_hasHydrated) {
-    return fallback ? <>{fallback}</> : <LoadingSpinner />;
-  }
-
   // Determine overall loading state
   const isLoading = authLoading || (isAuthenticated && !user && userLoading);
 

frontend/src/components/auth/index.ts

@@ -1,5 +1,8 @@
 // Authentication components
 
+// Auth initialization
+export { AuthInitializer } from './AuthInitializer';
+
 // Route protection
 export { AuthGuard } from './AuthGuard';