feat: CI pipeline, lint fixes, and Renovate config

- pyproject.toml with ruff/pytest config (setuptools<81 pin)
- Full test suite (26 tests)
- Gitea Actions CI (lint, test, docker, notify)
- Ruff lint/format fixes across source files
- Renovate config for automated dependency updates

Ref: ADR-0057

healthcheck.py

@@ -3,9 +3,10 @@
 Health check script for Kubernetes probes
 Verifies NATS connectivity
 """
-import sys
-import os
+
 import asyncio
+import os
+import sys
 
 import nats