Implement Password Grant Flow for Authentication and Enhance User Experience

- Introduced Password Grant Flow for user authentication, allowing direct login with email and password.
- Updated `useAuth` composable to manage login and logout processes, including Single Sign-Out from Cidaas.
- Enhanced user interface with a new `UserMenu` component displaying user information and logout functionality.
- Updated homepage to show personalized greetings for logged-in users and a login prompt for guests.
- Added logout confirmation page with a countdown redirect to the homepage.
- Documented the implementation details and future enhancements for OAuth2 flows in CLAUDE.md and other relevant documentation.
- Added test credentials and guidelines for automated testing in the new TESTING.md file.

app/composables/useAuth.ts

@@ -69,16 +69,24 @@ export function useAuth() {
 
   /**
    * Logout
-   * Clears session and redirects to homepage
+   * Performs Single Sign-Out at Cidaas and clears local session
+   * Redirects to logout confirmation page
    */
   async function logout() {
     try {
+      // Call logout endpoint (performs Cidaas SSO + clears session)
       await $fetch('/api/auth/logout', { method: 'POST' })
-      await clear() // Clear client-side state
-      navigateTo('/') // Redirect to homepage
+
+      // Clear client-side state
+      await clear()
+
+      // Redirect to logout confirmation page (with auto-redirect to homepage)
+      navigateTo('/logout')
     } catch (error) {
       console.error('Logout failed:', error)
-      throw error
+      // Even on error, clear local state and redirect
+      await clear()
+      navigateTo('/logout')
     }
   }