fix(model_tools): cancel coroutine on timeout so worker thread exits + log full traceback

_run_async() bridges sync tool handlers to async code. When the handler
is invoked from inside a running event loop (gateway / nested async),
it spawns a worker thread and blocks on future.result(timeout=300).

Before this change, a coroutine that ran past 300s leaked its worker
thread:

  - future.cancel() is a no-op on a running ThreadPoolExecutor future
    (cancel only works on not-yet-started work).
  - pool.shutdown(wait=False, cancel_futures=True) let the caller
    proceed but the worker kept running the coroutine until it
    returned on its own.

Every tool timeout leaked one thread. In long-lived gateway / RL
sessions this is cumulative.

The fix replaces bare asyncio.run() with a worker wrapper that
creates its own event loop. On timeout, _run_async schedules
task.cancel() on that loop via call_soon_threadsafe, then shuts the
pool down with wait=False so the caller returns immediately. The
coroutine observes CancelledError at its next await and the worker
thread exits cleanly.

Also switches logger.error() to logger.exception() in the top-level
handle_function_call() except block so tool failures produce full
stack traces in errors.log instead of just the message.

Related: #17420 (contributor flagged the leak; the original fix used
pool.shutdown(wait=True) which would have converted the leak into a
hang — caller blocks forever on the same stuck coroutine). Credit
for identifying the leak goes to the contributor.

Co-authored-by: 0z! <162235745+0z1-ghb@users.noreply.github.com>

scripts/release.py

@@ -60,6 +60,7 @@ AUTHOR_MAP = {
     "johnnncenaaa77@gmail.com": "johnncenae",
     "thomasjhon6666@gmail.com": "ThomassJonax",
     "focusflow.app.help@gmail.com": "yes999zc",
+    "162235745+0z1-ghb@users.noreply.github.com": "0z1-ghb",
     "yes999zc@163.com": "yes999zc",
     "343873859@qq.com": "DrStrangerUJN",
     "uzmpsk.dilekakbas@gmail.com": "dlkakbs",