feat: upgrade to qwen3.5, self-hosted Gitea CI, optimize Docker image

Model upgrade:
- qwen2.5:14b → qwen3.5:latest across config, tools, and docs
- Added qwen3.5 to multimodal model registry

Self-hosted Gitea CI:
- .gitea/workflows/tests.yml: lint + test jobs via act_runner
- Unified Dockerfile: pre-baked deps from poetry.lock for fast CI
- sitepackages=true in tox for ~2s dep resolution (was ~40s)
- OLLAMA_URL set to dead port in CI to prevent real LLM calls

Test isolation fixes:
- Smoke test fixture mocks create_timmy (was hitting real Ollama)
- WebSocket sends initial_state before joining broadcast pool (race fix)
- Tests use settings.ollama_model/url instead of hardcoded values
- skip_ci marker for Ollama-dependent tests, excluded in CI tox envs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/infrastructure/ws_manager/handler.py

@@ -36,9 +36,15 @@ class WebSocketManager:
         self._connections: list[WebSocket] = []
         self._event_history: collections.deque[WSEvent] = collections.deque(maxlen=100)
 
-    async def connect(self, websocket: WebSocket) -> None:
-        """Accept a new WebSocket connection."""
-        await websocket.accept()
+    async def connect(self, websocket: WebSocket, *, accept: bool = True) -> None:
+        """Accept a new WebSocket connection and add it to the broadcast pool.
+
+        Args:
+            websocket: The WebSocket to register.
+            accept: If False, skip the accept() call (caller already accepted).
+        """
+        if accept:
+            await websocket.accept()
         self._connections.append(websocket)
         logger.info(
             "WebSocket connected — %d active connections",