feat(agents): enforce one librarian timeout budget

- add LIBRARIAN_TIMEOUT config (default 180s) and enforce it with
  asyncio.wait_for inside delegate_to_librarian, covering the live
  paths (steward direct delegation and SSE streaming) that had no cap
- timeouts fail honestly: success=False with a curated butler sentence,
  detail in logs
- set an explicit timeout on TatlockOllamaProvider's AsyncOpenAI client
  from OLLAMA_TIMEOUT instead of the SDK default (~600s per LLM call)
- remove the contradictory unused 60s default from
  AgentRequest.timeout_seconds; coordination falls back to the
  configured budget

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/agents/test_delegation.py

@@ -193,6 +193,30 @@ class TestDelegateToLibrarian:
             assert "Connection refused" not in result.error
             assert "internal" not in result.error
 
+    @pytest.mark.asyncio
+    async def test_delegate_to_librarian_timeout(self, monkeypatch):
+        """Delegation is capped by LIBRARIAN_TIMEOUT and fails honestly."""
+        import asyncio
+
+        from src.core.config import config
+
+        async def slow_run(task, context=""):
+            await asyncio.sleep(5)
+            return "too late"
+
+        monkeypatch.setattr(config, "LIBRARIAN_TIMEOUT", 0.05)
+
+        with patch(
+            "src.agents.librarian.agent.run_librarian",
+            new=slow_run,
+        ):
+            result = await delegate_to_librarian(task="Search for information")
+
+        assert result.success is False
+        assert "longer than expected" in result.output
+        assert result.error is not None
+        assert "time budget" in result.error
+
     @pytest.mark.asyncio
     async def test_delegate_to_librarian_preserves_task(self):
         """Test delegation result preserves original task."""

tests/agents/test_protocol.py

@@ -27,7 +27,8 @@ class TestAgentRequest:
 
         assert request.task == "Find information about Docker"
         assert request.context == ""
-        assert request.timeout_seconds == 60
+        # No hardcoded default - None defers to the configured budget
+        assert request.timeout_seconds is None
 
     def test_request_with_context(self):
         """Test request with additional context."""