test: Docker build and PWA installation verified

- Verified multi-stage Dockerfile builds successfully (pnpm build passes)
- Improved .dockerignore for smaller build context
- Graceful shutdown wired: SIGTERM/SIGINT drain active fights (10s timeout)
- Migrations + mock bot seeding run on startup automatically
- PWA: manifest, service worker, icons, offline caching all configured
- Workbox caches app shell + fonts + TTS model, excludes API routes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.dockerignore

@@ -1,15 +1,17 @@
 node_modules
-dist
 .git
+.github
 .claude
+.pnpm-store
 *.db
+*.db-journal
 *.db-wal
 *.db-shm
-.DS_Store
-.env
-.env.local
-loop
-botfights.db
-server/data
+data/backups
 frontend/dist
 server/dist
+loop
+*.md
+!pnpm-workspace.yaml
+.env*
+.DS_Store