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

tests/conftest.py

@@ -0,0 +1,52 @@
+"""
+Pytest configuration and fixtures for tts-module tests.
+"""
+
+import asyncio
+import os
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+# Set test environment variables before importing
+os.environ.setdefault("NATS_URL", "nats://localhost:4222")
+os.environ.setdefault("XTTS_URL", "http://localhost:8000")
+os.environ.setdefault("OTEL_ENABLED", "false")
+os.environ.setdefault("VOICE_MODEL_STORE", "/tmp/test-voice-models")
+
+
+@pytest.fixture(scope="session")
+def event_loop():
+    """Create event loop for async tests."""
+    loop = asyncio.new_event_loop()
+    yield loop
+    loop.close()
+
+
+@pytest.fixture
+def sample_audio_bytes():
+    """Sample audio bytes for testing (silent 16-bit PCM)."""
+    return bytes([0x00] * 4096)
+
+
+@pytest.fixture
+def mock_nats():
+    """Mock NATS connection."""
+    nc = AsyncMock()
+    nc.publish = AsyncMock()
+    nc.subscribe = AsyncMock()
+    nc.close = AsyncMock()
+    return nc
+
+
+@pytest.fixture
+def mock_http_client():
+    """Mock httpx async client."""
+    client = AsyncMock()
+    response = MagicMock()
+    response.status_code = 200
+    response.content = bytes([0x00] * 2048)
+    response.raise_for_status = MagicMock()
+    client.post = AsyncMock(return_value=response)
+    client.aclose = AsyncMock()
+    return client