feat: add Docker image, production server and health check

- Multi-stage Dockerfile on node:24-slim, non-root, healthcheck, /app/data volume
- server.mjs wraps the Astro handler with brotli/gzip compression,
  security headers and graceful SIGTERM shutdown (npm start)
- GET /api/health/ reports server and view-counter DB status
- Move build-only packages to devDependencies (smaller runtime image)
- docker-compose.yml as an alternative for Dokploy Compose

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docker-compose.yml

@@ -0,0 +1,16 @@
+# Alternative to Dokploy's "Application" type: Dokploy → Create Service → Compose.
+# Domains/HTTPS are still configured in Dokploy's UI (Traefik); no host ports are published.
+services:
+  web:
+    build: .
+    restart: unless-stopped
+    environment:
+      NODE_ENV: production
+      DATA_DIR: /app/data
+    volumes:
+      - ta1sph-data:/app/data
+    expose:
+      - '4321'
+
+volumes:
+  ta1sph-data: