What does this PR do?

This PR fixes the remaining async-context gap in tools/homeassistant_tool.py's sync-to-async bridge.

The Home Assistant tool already reused persistent event loops for some sync call paths, but when _run_async() was invoked from inside an already-running event loop it still spawned a disposable thread and called asyncio.run(coro) per invocation. That per-call create-and-destroy loop behavior can leave aiohttp cleanup tied to dead loops, which risks Unclosed client session / Unclosed connector warnings in long-running Hermes processes.

This change makes that path reuse a dedicated persistent background loop thread instead, bringing the Home Assistant tool in line with Hermes' persistent-loop bridge pattern.

Related Issue

Fixes #13586

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✅ Tests (adding or improving test coverage)
• ✨ New feature (non-breaking change that adds functionality)
• 🔒 Security fix
• 📝 Documentation update
• ♻️ Refactor (no behavior change)
• 🎯 New skill (bundled or hub)

Changes Made

• update tools/homeassistant_tool.py so async-context calls no longer use per-call asyncio.run()
• add a dedicated persistent background loop thread for calls made while another event loop is already running
• submit async-context coroutines with asyncio.run_coroutine_threadsafe(...)
• keep the existing persistent main-thread and per-worker-thread loop behavior
• add regression coverage in tests/tools/test_homeassistant_tool.py for loop reuse and liveness from inside a running event loop

How to Test

1. Reproduce the bug scenario by calling tools/homeassistant_tool.py:_run_async() from within an already-running event loop.
2. Verify that the call succeeds without falling back to per-call asyncio.run() loop creation/destruction behavior.
3. Run the targeted regression tests:
   • python -m pytest tests/tools/test_homeassistant_tool.py -q -o 'addopts='
   • python -m pytest tests/gateway/test_homeassistant.py -q -o 'addopts='
4. Optional broader check: run pytest tests/ -q.

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform: Ubuntu 24.04

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) — or N/A
• I've updated cli-config.yaml.example if I added/changed config keys — or N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — or N/A
• I've considered cross-platform impact (Windows, macOS) per the compatibility guide — or N/A
• I've updated tool descriptions/schemas if I changed tool behavior — or N/A

Screenshots / Logs

Targeted local test results:

• tests/tools/test_homeassistant_tool.py: passed
• tests/gateway/test_homeassistant.py: passed

Note: I did not mark the full pytest tests/ -q checkbox as complete here because repository-wide baseline failures unrelated to this PR were observed separately.