feat: Implement collection deletion and loading spinners

- Add API endpoint and handler to delete collections
- Introduce LoadingSpinner component for async operations
- Show loading spinners during file loading and preview rendering
- Enhance modal accessibility by removing aria-hidden attribute
- Refactor delete functionality to distinguish between collections and files/folders
- Remove unused collection definitions from config

server_webdav.py

@@ -104,6 +104,10 @@ class MarkdownEditorApp:
         if path == '/fs/' and method == 'POST':
             return self.handle_create_collection(environ, start_response)
 
+        # API to delete a collection
+        if path.startswith('/api/collections/') and method == 'DELETE':
+            return self.handle_delete_collection(environ, start_response)
+
         # Check if path starts with a collection name (for SPA routing)
         # This handles URLs like /notes/ttt or /documents/file.md
         # MUST be checked BEFORE WebDAV routing to prevent WebDAV from intercepting SPA routes
@@ -205,7 +209,68 @@ class MarkdownEditorApp:
             print(f"Error creating collection: {e}")
             start_response('500 Internal Server Error', [('Content-Type', 'application/json')])
             return [json.dumps({'error': str(e)}).encode('utf-8')]
-    
+
+    def handle_delete_collection(self, environ, start_response):
+        """Delete a collection"""
+        try:
+            # Extract collection name from path: /api/collections/{name}
+            path = environ.get('PATH_INFO', '')
+            collection_name = path.split('/')[-1]
+
+            if not collection_name:
+                start_response('400 Bad Request', [('Content-Type', 'application/json')])
+                return [json.dumps({'error': 'Collection name is required'}).encode('utf-8')]
+
+            # Check if collection exists
+            if collection_name not in self.collections:
+                start_response('404 Not Found', [('Content-Type', 'application/json')])
+                return [json.dumps({'error': f'Collection "{collection_name}" not found'}).encode('utf-8')]
+
+            # Get collection path
+            collection_config = self.collections[collection_name]
+            collection_path = Path(collection_config['path'])
+
+            # Delete the collection directory and all its contents
+            import shutil
+            if collection_path.exists():
+                shutil.rmtree(collection_path)
+                print(f"Deleted collection directory: {collection_path}")
+
+            # Remove from collections dict
+            del self.collections[collection_name]
+
+            # Update config file
+            self.save_config()
+
+            # Remove from WebDAV provider mapping
+            provider_key = f'/fs/{collection_name}'
+            if hasattr(self.webdav_app, 'provider_map') and provider_key in self.webdav_app.provider_map:
+                del self.webdav_app.provider_map[provider_key]
+                print(f"Removed provider from provider_map: {provider_key}")
+
+            # Remove from sorted_share_list if it exists
+            if hasattr(self.webdav_app, 'sorted_share_list') and provider_key in self.webdav_app.sorted_share_list:
+                self.webdav_app.sorted_share_list.remove(provider_key)
+                print(f"Removed from sorted_share_list: {provider_key}")
+
+            print(f"Deleted collection '{collection_name}'")
+
+            response_body = json.dumps({'success': True, 'name': collection_name}).encode('utf-8')
+            start_response('200 OK', [
+                ('Content-Type', 'application/json'),
+                ('Content-Length', str(len(response_body))),
+                ('Access-Control-Allow-Origin', '*')
+            ])
+
+            return [response_body]
+
+        except Exception as e:
+            print(f"Error deleting collection: {e}")
+            import traceback
+            traceback.print_exc()
+            start_response('500 Internal Server Error', [('Content-Type', 'application/json')])
+            return [json.dumps({'error': str(e)}).encode('utf-8')]
+
     def handle_static(self, environ, start_response):
         """Serve static files"""
         path = environ.get('PATH_INFO', '')[1:]  # Remove leading /