feat(frontend): scaffold PWA with LiveKit join flow

Vite + React + TS + Tailwind v4, installable PWA. Join-pod UI that fetches a
LiveKit token from the backend, connects to the pod room, and publishes screen
+ mic so PodMan can watch.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/tsconfig.json

@@ -0,0 +1,9 @@
+{
+  "extends": "../tsconfig.base.json",
+  "compilerOptions": {
+    "lib": ["ES2023", "DOM", "DOM.Iterable"],
+    "jsx": "react-jsx",
+    "noEmit": true
+  },
+  "include": ["src", "vite.config.ts"]
+}