T1/Phase 1: scaffold Vite SPA + Hono API + Bun worker

- apps/web: Vite + React 19 + TanStack Router/Query + shadcn/ui
   - apps/api: Hono + Bun on :3001 with /api/health, /api/auth/*, /mcp stubs
   - apps/worker: Bun worker stub, DB connection, graceful SIGTERM
   - apps/web-legacy/: old Next.js code moved aside (preserved for T2-T8 reference)
   - Dockerfiles: api (Bun), worker (Bun), spa (multi-stage Caddy)
   - Caddyfile: serves dist + reverse-proxies /api/* + /mcp to api
   - docker-compose.yml: 4-service target (api, spa, db, worker)
   - packages/db/src/client.ts: shared Drizzle client for api + worker
   - db/client.ts: root-level alias for convenience

   Parent: t_e1cbd87d -> t_24c9c3fd (T0)

apps/web/src/main.tsx

@@ -0,0 +1,27 @@
+import React from "react";
+import ReactDOM from "react-dom/client";
+import { RouterProvider, createRouter } from "@tanstack/react-router";
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { routeTree } from "./routeTree";
+import "./index.css";
+
+const queryClient = new QueryClient();
+
+const router = createRouter({ routeTree });
+
+declare module "@tanstack/react-router" {
+  interface Register {
+    router: typeof router;
+  }
+}
+
+const rootEl = document.getElementById("root");
+if (!rootEl) throw new Error("Root element not found");
+
+ReactDOM.createRoot(rootEl).render(
+  <React.StrictMode>
+    <QueryClientProvider client={queryClient}>
+      <RouterProvider router={router} />
+    </QueryClientProvider>
+  </React.StrictMode>
+);