fix(mcp): report configured timeout in MCP call errors

Track elapsed wall time in _run_on_mcp_loop, cancel the in-flight future when a timeout expires, and raise a descriptive TimeoutError that includes the elapsed and configured timeout. Add regression coverage for the new timeout diagnostics.

tests/tools/test_mcp_tool.py

@@ -547,6 +547,43 @@ class TestRunOnMCPLoopInterrupts:
             mcp_mod._mcp_loop = old_loop
             mcp_mod._mcp_thread = old_thread
 
+    def test_timeout_reports_elapsed_and_configured_timeout(self):
+        import tools.mcp_tool as mcp_mod
+
+        loop = asyncio.new_event_loop()
+        thread = threading.Thread(target=loop.run_forever, daemon=True)
+        thread.start()
+
+        cancelled = threading.Event()
+
+        async def _slow_call():
+            try:
+                await asyncio.sleep(5)
+                return "done"
+            except asyncio.CancelledError:
+                cancelled.set()
+                raise
+
+        old_loop = mcp_mod._mcp_loop
+        old_thread = mcp_mod._mcp_thread
+        mcp_mod._mcp_loop = loop
+        mcp_mod._mcp_thread = thread
+
+        try:
+            with pytest.raises(TimeoutError, match=r"MCP call timed out after .*configured timeout: 0.2s"):
+                mcp_mod._run_on_mcp_loop(_slow_call(), timeout=0.2)
+
+            deadline = time.time() + 2
+            while time.time() < deadline and not cancelled.is_set():
+                time.sleep(0.05)
+            assert cancelled.is_set()
+        finally:
+            loop.call_soon_threadsafe(loop.stop)
+            thread.join(timeout=2)
+            loop.close()
+            mcp_mod._mcp_loop = old_loop
+            mcp_mod._mcp_thread = old_thread
+
 
 # ---------------------------------------------------------------------------
 # Tool registration (discovery + register)