add initial Docker setup with .dockerignore, Dockerfile, docker-compose.yml, and deployment script

.gitignore

@@ -19,6 +19,10 @@ npm-debug.log*
 # Environment files
 .env
 .env.*
+!.env.example
+
+# Deploy secrets (server password / host) — keep the .example tracked
+deploy.config
 
 # Build output
 dist/