fix: wait for auth initialization in guards to prevent race condition

This fixes the race condition where guards check authentication before
AuthService finishes loading the session, causing false redirects to
login even when users are authenticated.

Problem:
- AuthService.initializeAuth() is async and called in constructor
- Guards were checking isAuthenticated() immediately
- If auth still loading, user is null → guard redirects to login
- This caused all E2E tests to fail with timeouts and missing elements

Solution:
- Added waitForAuthReady() method in AuthService that waits for
  loading state to complete
- Updated authGuard to await auth initialization before checking
- Updated adminGuard to await auth initialization before checking
- Uses efficient polling with 50ms intervals

This ensures:
1. Guards always check auth status AFTER session is loaded
2. No false redirects to login for authenticated users
3. E2E tests can properly navigate protected routes
4. Admin panel routes accessible to admin users

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: klagrida

frontend/src/app/guards/admin-guard.ts

@@ -6,6 +6,9 @@ export const adminGuard: CanActivateFn = async (route, state) => {
   const authService = inject(AuthService);
   const router = inject(Router);
 
+  // Wait for auth state to finish loading
+  await authService.waitForAuthReady();
+
   // Check if user is authenticated
   if (!authService.isAuthenticated()) {
     return router.createUrlTree(['/login'], {

frontend/src/app/guards/auth-guard.ts

@@ -2,10 +2,13 @@ import { inject } from '@angular/core';
 import { CanActivateFn, Router } from '@angular/router';
 import { AuthService } from '../services/auth.service';
 
-export const authGuard: CanActivateFn = (route, state) => {
+export const authGuard: CanActivateFn = async (route, state) => {
   const authService = inject(AuthService);
   const router = inject(Router);
 
+  // Wait for auth state to finish loading
+  await authService.waitForAuthReady();
+
   if (authService.isAuthenticated()) {
     return true;
   }

frontend/src/app/services/auth.service.ts

@@ -112,6 +112,27 @@ export class AuthService {
     return data;
   }
 
+  /**
+   * Wait for auth initialization to complete
+   * Returns a promise that resolves when auth state is loaded
+   */
+  async waitForAuthReady(): Promise<void> {
+    // If already loaded, return immediately
+    if (!this.authState().loading) {
+      return;
+    }
+
+    // Wait for loading to complete
+    return new Promise((resolve) => {
+      const checkInterval = setInterval(() => {
+        if (!this.authState().loading) {
+          clearInterval(checkInterval);
+          resolve();
+        }
+      }, 50);
+    });
+  }
+
   /**
    * Check if user is authenticated
    */