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>

Dockerfile

@@ -0,0 +1,43 @@
+# Stage 1: Install dependencies
+FROM node:22-slim AS deps
+RUN corepack enable && corepack prepare pnpm@latest --activate
+WORKDIR /app
+COPY package.json pnpm-workspace.yaml pnpm-lock.yaml ./
+COPY frontend/package.json frontend/
+COPY server/package.json server/
+RUN pnpm install --frozen-lockfile
+
+# Stage 2: Build frontend
+FROM deps AS build-fe
+COPY frontend/ frontend/
+RUN pnpm --filter frontend build
+
+# Stage 3: Build server
+FROM deps AS build-be
+COPY server/ server/
+RUN pnpm --filter server build
+
+# Stage 4: Production image
+FROM node:22-slim AS production
+RUN corepack enable && corepack prepare pnpm@latest --activate
+WORKDIR /app
+
+COPY package.json pnpm-workspace.yaml pnpm-lock.yaml ./
+COPY server/package.json server/
+RUN pnpm install --filter server --prod --frozen-lockfile
+
+# Copy built server
+COPY --from=build-be /app/server/dist server/dist
+
+# Copy built frontend into server's public dir
+COPY --from=build-fe /app/frontend/dist server/public
+
+# Data volume for SQLite
+RUN mkdir -p /app/server/data
+VOLUME /app/server/data
+
+ENV NODE_ENV=production
+ENV PORT=9100
+EXPOSE 9100
+
+CMD ["node", "server/dist/index.js"]