[ci skip] f1-stream: add CDN token refresh, SvelteKit frontend, multi-stream layout (Phases 6-8)

- Phase 6: CDN token lifecycle with 3-strategy URL matching and periodic refresh
- Phase 7: SvelteKit 2/Svelte 5 frontend with schedule calendar and hls.js player
- Phase 8: Multi-stream layout supporting up to 4 simultaneous HLS streams
- Update Dockerfile to multi-stage build (Node.js frontend + Python backend)
- Switch deployment to :latest tag with Always pull policy for CI-driven deploys
- Update Woodpecker CI to use explicit latest tag

stacks/f1-stream/files/Dockerfile

@@ -1,3 +1,15 @@
+## Stage 1: Build frontend
+FROM node:22-slim AS frontend-builder
+
+WORKDIR /frontend
+
+COPY frontend/package.json frontend/package-lock.json* ./
+RUN npm install
+
+COPY frontend/ ./
+RUN npm run build
+
+## Stage 2: Python backend + static frontend
 FROM python:3.13-slim-bookworm
 
 WORKDIR /app
@@ -7,6 +19,9 @@ RUN pip install --no-cache-dir -r requirements.txt
 
 COPY backend/ ./backend/
 
+# Copy built frontend into the image
+COPY --from=frontend-builder /frontend/build ./frontend/build
+
 EXPOSE 8000
 
 CMD ["uvicorn", "backend.main:app", "--host", "0.0.0.0", "--port", "8000"]