T9/Phase 7: deploy 4-container compose + Caddy reverse proxy

- docker-compose.yml: 4 services (db, api, spa, worker), Next.js removed
- Dockerfile.api: Bun base, install, run
- Dockerfile.worker: Bun base, install, run
- Dockerfile.spa: multi-stage (Bun build -> Caddy serve), fixed lockfile + workspace stubs
- Caddyfile: serve SPA + reverse-proxy /api/* + /mcp, SPA fallback routing
- Old Node worker stopped, replaced with new Bun worker
- Old Next.js server on :3000 stopped
- BASELINE.md: Phase 7 Deploy section added
- DEPLOY.md: deploy/rollback/debug guide added

Dockerfile.spa

@@ -2,11 +2,21 @@
 FROM oven/bun:1.3 AS builder
 WORKDIR /app
 
-COPY package.json bunfig.toml ./
-COPY apps/web/package.json apps/web/
+# Copy workspace manifests + lockfile
+COPY package.json bunfig.toml bun.lock ./
+COPY apps/web/package.json apps/web/package.json
+COPY apps/api/package.json apps/api/package.json
+COPY apps/worker/package.json apps/worker/package.json
+COPY packages/db/package.json packages/db/package.json
+COPY packages/shared/package.json packages/shared/package.json
+
+# Install dependencies (workspace-aware)
 RUN bun install --frozen-lockfile 2>/dev/null || bun install
 
+# Copy full web app source
 COPY apps/web ./apps/web
+
+# Build the SPA
 RUN cd apps/web && bun run build
 
 # Serve stage