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>

src/pages/api/health.ts

@@ -0,0 +1,13 @@
+import type { APIRoute } from 'astro';
+import { dbHealthy } from '../../lib/views';
+
+export const prerender = false;
+
+// GET /api/health — Docker HEALTHCHECK / Dokploy. 503 if the view-counter DB is unavailable.
+export const GET: APIRoute = () => {
+  const db = dbHealthy();
+  return Response.json(
+    { status: db ? 'ok' : 'degraded', db },
+    { status: db ? 200 : 503, headers: { 'Cache-Control': 'no-store' } },
+  );
+};