Implement Official Keycloak JS Adapter with Proxy-Aware Configuration

MAJOR ENHANCEMENT: Complete Keycloak integration with proper HTTPS/proxy handling

## Core Improvements:

### 1. Enhanced Configuration (nuxt.config.ts)
- Added proxy trust configuration for nginx environments
- Configured baseUrl for production HTTPS enforcement
- Added debug mode configuration for development

### 2. Proxy-Aware Keycloak Composable (composables/useKeycloak.ts)
- Intelligent base URL detection (production vs development)
- Force HTTPS redirect URIs in production environments
- Enhanced debugging and logging capabilities
- Proper PKCE implementation for security
- Automatic token refresh mechanism

### 3. Dual Authentication System
- Updated middleware to support both Directus and Keycloak
- Enhanced useUnifiedAuth for seamless auth source switching
- Maintains backward compatibility with existing Directus users

### 4. OAuth Flow Implementation
- Created proper callback handler (pages/auth/callback.vue)
- Comprehensive error handling and user feedback
- Automatic redirect to dashboard on success

### 5. Enhanced Login Experience (pages/login.vue)
- Restored SSO login button with proper error handling
- Maintained existing Directus login form
- Clear separation between auth methods with visual divider

### 6. Comprehensive Testing Suite (pages/dashboard/keycloak-test.vue)
- Real-time configuration display
- Authentication status monitoring
- Interactive testing tools
- Detailed debug logging system

## Technical Solutions:

 **Proxy Detection**: Automatically detects nginx proxy and uses correct HTTPS URLs
 **HTTPS Enforcement**: Forces secure redirect URIs in production
 **Error Handling**: Comprehensive error catching with user-friendly messages
 **Debug Capabilities**: Enhanced logging for troubleshooting
 **Security**: Implements PKCE and secure token handling

## Infrastructure Compatibility:
- Works with nginx reverse proxy setups
- Compatible with Docker container networking
- Handles SSL termination at proxy level
- Supports both development and production environments

This implementation specifically addresses the HTTP/HTTPS redirect URI mismatch
that was causing 'unauthorized_client' errors in the proxy environment.

middleware/authentication.ts

@@ -6,7 +6,7 @@ export default defineNuxtRouteMiddleware(async (to) => {
   const isAuthRequired = to.meta.auth !== false;
   
   try {
-    // Only use Directus auth for now (disable Keycloak temporarily)
+    // Check Directus auth first (most reliable)
     const { fetchUser, setUser } = useDirectusAuth();
     const directusUser = useDirectusUser();
     
@@ -27,6 +27,28 @@ export default defineNuxtRouteMiddleware(async (to) => {
       return;
     }
 
+    // Check Keycloak auth if authentication is required
+    if (isAuthRequired) {
+      const keycloak = useKeycloak();
+      
+      // Initialize Keycloak if not already done
+      if (!keycloak.isInitialized.value) {
+        try {
+          const authenticated = await keycloak.initKeycloak();
+          if (authenticated) {
+            // User authenticated with Keycloak
+            return;
+          }
+        } catch (error) {
+          console.error('Keycloak initialization failed:', error);
+          // Continue to login redirect
+        }
+      } else if (keycloak.isAuthenticated.value) {
+        // User already authenticated with Keycloak
+        return;
+      }
+    }
+
     // No authentication found
     if (isAuthRequired) {
       // Redirect to login page