feat: production deployment — Dockerfile, docker-compose, SPA serving, classic bot fights

- Add Dockerfile (multi-stage: build frontend + server, serve from single container)
- Add docker-compose.yml for Portainer stack deployment
- Server serves frontend SPA in production (static assets + SPA fallback)
- Auto-run migrations and seed mock bots on server startup
- DB path configurable via DB_PATH env var
- Add "Fight a Classic Bot" button for instant mock bot matches
- FIGHT button queues for real AI opponents

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

.dockerignore

@@ -0,0 +1,15 @@
+node_modules
+dist
+.git
+.claude
+*.db
+*.db-wal
+*.db-shm
+.DS_Store
+.env
+.env.local
+loop
+botfights.db
+server/data
+frontend/dist
+server/dist