Add docker-compose support with environment variable configuration

- Create docker-compose.yml with server and agent services
- Add environment variable support to Dockerfiles via entrypoint scripts
- Configure server with ADDR, PORT, USERNAME, PASSWORD vars
- Configure agent with SERVER, INTERVAL, AGENT_ID vars
- Add health check to server service for container orchestration
- Add service dependencies to ensure server starts before agent
- Create .dockerignore to optimize Docker builds
- Update QUICKSTART.md with Docker Compose instructions
- Support running server only, agent only, or full stack
- Support multiple agents with custom identifiers

.dockerignore

@@ -0,0 +1,39 @@
+# Git
+.git
+.gitignore
+.gitattributes
+
+# Development
+.vscode
+.idea
+*.swp
+*.swo
+*~
+.DS_Store
+
+# Build artifacts
+bin/
+dist/
+*.o
+*.a
+*.so
+
+# Dependencies
+vendor/
+
+# Documentation
+*.md
+RELEASE.md
+README.md
+QUICKSTART.md
+AGENTS.md
+
+# Other
+docker-compose.yml
+Dockerfile
+Dockerfile.server
+Dockerfile.agent
+.dockerignore
+.github
+.gitea
+scripts/