feat: custom voice support, CI pipeline, and Renovate config

- VoiceRegistry for trained voices from Kubeflow pipeline
- Custom voice routing in synthesize()
- NATS subjects for listing/refreshing voices
- pyproject.toml with ruff/pytest config
- Full test suite (26 tests)
- Gitea Actions CI (lint, test, docker, notify)
- Renovate config for automated dependency updates

Ref: ADR-0056, 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