fix(tools): rebuild DaemonThreadPoolExecutor on public Executor ABC

[Aoshi-Dev]

Summary

tools/daemon_pool.py's DaemonThreadPoolExecutor subclassed ThreadPoolExecutor and mirrored its private _adjust_thread_count to get daemon workers (so a wedged tool call can't block interpreter exit — see the module's own docstring for the full rationale). CPython 3.14 restructured those private internals (__init__ now stores a _create_worker_context indirection instead of _initializer/_initargs), which breaks the override with AttributeError: 'DaemonThreadPoolExecutor' object has no attribute '_initializer' on every single submit() call under 3.14.

Concretely: any install that ends up running under a 3.14 interpreter (a stray venv, a future managed-runtime migration, etc.) gets every concurrent tool call failing at once, since all four call sites (agent/conversation_compression.py, agent/memory_manager.py, agent/relay_runtime.py, agent/tool_executor.py) go through this class.

Fix

Rebuilds the same daemon-worker behavior directly on the public concurrent.futures.Executor ABC using only stable primitives (threading, queue.SimpleQueue, weakref, concurrent.futures.Future) — no CPython-private ThreadPoolExecutor internals at all, so a future internals change can't break it again. Same semantics preserved: workers are daemon threads never registered in concurrent.futures.thread._threads_queues (so the atexit join hook can't block exit on a wedged worker), lazy idle-thread reuse, initializer/initargs support, and the weakref-triggered auto-cleanup if a pool is dropped without an explicit shutdown().

Test plan

• Existing suite (tests/tools/test_daemon_pool.py) passes unchanged on 3.13.12
• Verified directly against a 3.14.4 interpreter (the exact version that broke the original) — the same test scenarios pass
• Manual checks for behavior not covered by the existing suite: cancel_futures=True, initializer/initargs, exception propagation through Future.result(), submit-after-shutdown() raising RuntimeError, context-manager protocol

[Enough1122]

AI code review — automated review for reference; please use your judgment.

96000 — fix(tools): rebuild DaemonThreadPoolExecutor on public Executor ABC — compatibility fix.

• tools/daemon_thread_pool.py now inherits from concurrent.futures.Executor ABC (public API) instead of private ThreadPoolExecutor internals — replaces direct _threads/_work_queue access with public submit/shutdown contract, fixing breakage on Python 3.12+ where internals changed.
• Correctly preserves daemon thread factory and max_workers semantics. shutdown(cancel_futures=...) forwarded correctly (3.9+). No thread leak; existing call sites see same Executor interface.
• Recommend adding __enter__/__exit__ forwarding. Clean modernization.