Problem: FunctionTool.run() is already executing inside an async method, but the sync-function path asks the event loop policy via asyncio.get_event_loop() before dispatching work to the executor.

Before / after: before, both executor calls used asyncio.get_event_loop().run_in_executor(...). After, the method captures the active running loop once with asyncio.get_running_loop() and reuses it for both executor paths, while preserving cancellation-token linking and the existing executor behavior.

Verification:

• python -m py_compile python\packages\autogen-core\src\autogen_core\tools\_function_tool.py