Flatten repo structure: move crawler/ to root, remove vqa/ and immoweb/

The crawler subdirectory was the only active project. Moving it to the
repo root simplifies paths and removes the unnecessary nesting. The
vqa/ and immoweb/ directories were legacy/unused and have been removed.

Updated .drone.yml, .gitignore, .claude/ docs, and skills to reflect
the new flat structure.

frontend/src/main.tsx

@@ -0,0 +1,15 @@
+import { StrictMode } from 'react';
+import { createRoot } from 'react-dom/client';
+import App from './App.tsx';
+import './index.css';
+
+import { AuthProvider } from "react-oidc-context";
+import { oidcConfig } from './auth/config.ts';
+
+createRoot(document.getElementById('root')!).render(
+  <StrictMode>
+    <AuthProvider {...oidcConfig}>
+      <App />
+    </AuthProvider>
+  </StrictMode>,
+)