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.

server/api/auth/logout.post.ts

@@ -3,7 +3,7 @@
 /**
  * POST /api/auth/logout
  *
- * End user session and clear session cookie
+ * End user session and perform Single Sign-Out at Cidaas
  *
  * Response:
  * {
@@ -12,13 +12,34 @@
  */
 
 export default defineEventHandler(async (event) => {
-  // Clear session (nuxt-auth-utils)
-  await clearUserSession(event)
+  try {
+    // 1. Get session to retrieve access token
+    const session = await getUserSession(event)
 
-  // Optional: Revoke Cidaas tokens (Single Sign-Out)
-  // This would require storing refresh_token in session and calling Cidaas revoke endpoint
+    // 2. If access token exists, logout from Cidaas (Single Sign-Out)
+    if (session.accessToken) {
+      try {
+        await logoutFromCidaas(session.accessToken)
+      } catch (error) {
+        // Log error but continue with local logout
+        console.error('Cidaas logout failed, continuing with local logout:', error)
+      }
+    }
 
-  return {
-    success: true,
+    // 3. Clear local session (nuxt-auth-utils)
+    await clearUserSession(event)
+
+    return {
+      success: true,
+    }
+  } catch (error) {
+    console.error('Logout error:', error)
+
+    // Clear session even if Cidaas logout fails
+    await clearUserSession(event)
+
+    return {
+      success: true, // Always return success for logout
+    }
   }
 })