refactor: port backend and frontend to TypeScript classes (bun + vite)

Backend (src/server, runs on Bun):
- GibbzHttpServer (health, /api/ice, /api/rooms, static, keepalive tuning)
- SignalingServer with Peer/Room/RoomRegistry classes and typed messages
- IceConfigProvider (env STUN/TURN + coturn HMAC ephemeral creds)
- StaticFileServer (dist/ with public/ fallback, traversal guard)
- Tracing (OpenTelemetry SDK), AppConfig; createApp() factory for tests

Frontend (src/client, built by Vite):
- VoiceApp orchestrator implementing VoiceAppContext
- WebRtcManager + PeerSession (perfect negotiation, pc rebuild, quality monitor)
- SignalingClient + ReconnectController, AudioManager, SpatialAudio,
  Microphone/ScreenShare controllers, ScreensUi/RosterUi/SpatialMap/
  SpeakingMonitor, Settings/Welcome dialogs, LayoutManager, MatrixChat

Tooling: bun scripts (dev/start/test/typecheck), vite.config.ts root
src/client with publicDir public/static, vitest-config for CI-less runs,
bun-based Dockerfile (oven/bun:1), Makefile + README updated, legacy
server.js/tracing.js/test.js/public js removed.

Verified locally: tsc --noEmit clean, vitest run 6/6 green, vite build ok,
server smoke-tested serving dist + signaling endpoints under Node. Local
bun binary segfaults (SIGILL) on this host, so 'bun test' itself was not
executable here; tests are vitest-API compatible which bun test maps.

package.json

@@ -1,12 +1,18 @@
 {
   "name": "Gameflow",
   "private": true,
+  "type": "module",
   "version": "0.1.0",
   "description": "WebRTC voice chat + screen sharing + spatial audio",
   "scripts": {
+    "dev": "vite",
+    "dev:server": "bun --watch src/server/index.ts",
     "build": "vite build",
-    "start": "node server.js",
-    "test": "node --test"
+    "start": "bun src/server/index.ts",
+    "typecheck": "tsc --noEmit",
+    "test": "bun test",
+    "test:node": "vitest run",
+    "check": "bun run typecheck && bun test"
   },
   "dependencies": {
     "@opentelemetry/api": "^1.9.1",
@@ -22,10 +28,14 @@
     "ws": "^8.18.0"
   },
   "devDependencies": {
+    "@types/bun": "^1.2.0",
+    "@types/ws": "^8.18.0",
     "@vitejs/plugin-basic-ssl": "^2.3.0",
     "esbuild": "^0.28.2",
+    "typescript": "^5.6.0",
     "vite": "^8.3.0",
-    "vite-plugin-node-polyfills": "^0.28.0"
+    "vite-plugin-node-polyfills": "^0.28.0",
+    "vitest": "^3.0.0"
   },
   "allowScripts": {
     "esbuild@0.28.2": true