Initial scaffold: full-stack RackMapper application

Complete project scaffold with working auth, REST API, Prisma/SQLite
schema, Docker config, and React frontend for both Rack Planner and
Service Mapper modules. Both server and client pass TypeScript strict
mode with zero errors. Initial migration applied.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/src/main.tsx

@@ -0,0 +1,15 @@
+import { StrictMode } from 'react';
+import { createRoot } from 'react-dom/client';
+import { Toaster } from 'sonner';
+import App from './App';
+import './index.css';
+
+const root = document.getElementById('root');
+if (!root) throw new Error('Root element not found');
+
+createRoot(root).render(
+  <StrictMode>
+    <App />
+    <Toaster theme="dark" position="bottom-right" richColors closeButton />
+  </StrictMode>
+);