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.

Dockerfile

@@ -1,30 +1,37 @@
+# gibbz voice — Bun runtime, Vite-built TypeScript client
 ARG APP_RELEASE=dev
 
-FROM node:22-alpine AS app
-
+FROM oven/bun:1 AS build
 WORKDIR /app
 
-COPY package*.json ./
+COPY package.json bun.lock* ./
+RUN bun install
 
-RUN npm ci
-
-COPY server.js tracing.js vite.config.mjs ./
-COPY public/ ./public/
+COPY tsconfig.json vite.config.ts ./
+COPY src ./src
+COPY public ./public
 
 # Inject build release into index.html if APP_RELEASE is specified
 ARG APP_RELEASE
 ENV APP_RELEASE=${APP_RELEASE}
 RUN if [ -n "${APP_RELEASE}" ]; then \
-      sed -i "s/window.__APP_RELEASE__ || \"dev\"/\"${APP_RELEASE}\"/g" ./public/index.html; \
+      sed -i "s/window.__APP_RELEASE__ || \"dev\"/\"${APP_RELEASE}\"/g" ./src/client/index.html; \
     fi
 
-RUN npm run build && npm prune --omit=dev
+RUN bun run build && bun install --production
+
+FROM oven/bun:1
+WORKDIR /app
+
+COPY --from=build /app/node_modules ./node_modules
+COPY --from=build /app/dist ./dist
+COPY --from=build /app/src/server ./src/server
 
 ENV PORT=8080 \
     HOST=0.0.0.0
 
 EXPOSE 8080
 
-USER node
+USER bun
 
-CMD ["node", "server.js"]
+CMD ["bun", "src/server/index.ts"]