Enhance public access and error handling in site-related views and loaders

- Updated `DebugScopedRateThrottle` to allow public access for blueprint list requests with site filters.
- Modified `SiteViewSet` and `SiteBlueprintViewSet` to permit public read access for list requests.
- Enhanced `loadSiteDefinition` to resolve site slugs to IDs, improving the loading process for site definitions.
- Improved error handling in `SiteDefinitionView` and `loadSiteDefinition` for better user feedback.
- Adjusted CSS styles for better layout and alignment in shared components.

backend/igny8_core/api/throttles.py

@@ -28,11 +28,19 @@ class DebugScopedRateThrottle(ScopedRateThrottle):
         - IGNY8_DEBUG_THROTTLE environment variable is True
         - User belongs to aws-admin or other system accounts
         - User is admin/developer role
+        - Public blueprint list request with site filter (for Sites Renderer)
         """
         # Check if throttling should be bypassed
         debug_bypass = getattr(settings, 'DEBUG', False)
         env_bypass = getattr(settings, 'IGNY8_DEBUG_THROTTLE', False)
         
+        # Bypass for public blueprint list requests (Sites Renderer fallback)
+        public_blueprint_bypass = False
+        if hasattr(view, 'action') and view.action == 'list':
+            if hasattr(request, 'query_params') and request.query_params.get('site'):
+                if not request.user or not hasattr(request.user, 'is_authenticated') or not request.user.is_authenticated:
+                    public_blueprint_bypass = True
+        
         # Bypass for system account users (aws-admin, default-account, etc.)
         system_account_bypass = False
         if hasattr(request, 'user') and request.user and hasattr(request.user, 'is_authenticated') and request.user.is_authenticated:
@@ -47,7 +55,7 @@ class DebugScopedRateThrottle(ScopedRateThrottle):
                 # If checking fails, continue with normal throttling
                 pass
         
-        if debug_bypass or env_bypass or system_account_bypass:
+        if debug_bypass or env_bypass or system_account_bypass or public_blueprint_bypass:
             # In debug mode or for system accounts, still set throttle headers but don't actually throttle
             # This allows testing throttle headers without blocking requests
             if hasattr(self, 'get_rate'):