feat: add native Windows broadcaster and live score modules

- streamer/windows: vash-broadcast.exe (setup/login/start/stop/status/doctor)
  with per-instance OBS, tosu and FFmpeg, a supervised worker, OCR room
  selection and OBS scene reconciliation; built and tested on Linux only
- streamer/relay.ts shared with Vash TV; Cloudflare Access proxy for dev/staging
- worker status validation and live score helpers for the site
- STREAMING_HANDOFF.md and streamer/ALPHA_TEST.md record what is unverified

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

streamer/tourney/Dockerfile

@@ -3,7 +3,7 @@
 FROM oven/bun:1 AS build
 WORKDIR /src
 COPY tv/main.ts tv/main.ts
-COPY agent.ts obs.ts tosu.ts tourney.ts ./
+COPY agent.ts obs.ts tosu.ts tourney.ts link.ts relay.ts vash-api.ts ./
 RUN bun build tv/main.ts --compile --minify --outfile /vash-tv \
  && bun build agent.ts --compile --minify --outfile /vash-agent