Async client garbage collection silently skips connection cleanup without a running loop #356

Description

The README says underlying HTTP connections are closed when the client is garbage collected, but the async HTTP wrapper can only schedule aclose() when garbage collection happens inside a running event loop.

If an AsyncStagehand client becomes unreachable after asyncio.run() returns (or in other code with no active loop), AsyncHttpxClientWrapper.__del__ catches RuntimeError from asyncio.get_running_loop() and silently does nothing. The connection pool is left unclosed.

There is already a TODO in the implementation noting that only asyncio runtimes are supported, but the no-running-loop case is also unhandled.

Reproduction

import gc
import asyncio

from stagehand import AsyncStagehand

async def create_client():
    return AsyncStagehand()

client = asyncio.run(create_client())
del client
gc.collect()  # runs after asyncio.run() closed its loop

At src/stagehand/_base_client.py:1416-1424, the finalizer attempts:

asyncio.get_running_loop().create_task(self.aclose())

There is no running loop at gc.collect(), and the broad except Exception: pass suppresses the failure without closing or warning.

Expected behavior

Either async clients should have a reliable cleanup strategy for this case, or the finalizer should emit a ResourceWarning and the documentation should clearly state that async clients are not automatically closed by garbage collection and must use async with / await close().

Actual behavior

Cleanup is silently skipped, contradicting the unconditional garbage-collection claim in README.md:678-680.

Why this matters

Unclosed async clients retain connection pools and sockets. Silence makes leaks hard to diagnose, particularly in test runners, notebooks, and applications that construct a client in one event-loop lifetime and release it later.

Prior-art check

I searched open/closed issues and PRs for unclosed AsyncStagehand, garbage collection, AsyncHttpxClientWrapper, and missing running loops and found no existing report.