feat(config): hot reload via SIGHUP and -watch flag

feat: add prometheus metrics, CORS, deep health checks, enhanced docs and roadmap

test(ratelimit): add unit tests for global and per-tool rate limiting

test(audit): add unit tests for structured audit logging

test(middleware): add unit tests for request ID middleware

feat(middleware): add request ID middleware for distributed tracing

test(mcp): add unit tests for JSON-RPC message parsing and serialization

test(config): add unit tests for YAML config loading and validation

test(policy): add unit tests for tool-level access control engine

test(auth): add comprehensive unit tests for auth middleware

docs: add README with badges, architecture, and roadmap

Add CI workflow (build, test, vet, lint)

Add example gateway configuration

Add multi-stage Docker build

feat: add CLI entrypoint with middleware chain and graceful shutdown