[Bifras]

What does this PR do?

Fixes the Windows gateway bootstrap so it loads Python dependencies from PM's committed environment instead of the hardcoded pre-PM in-tree venv/.

gateway/run.py::_ensure_windows_gateway_venv_imports() always appended project_root / "venv" to its candidate list before asking PM. On a migrated (PM-managed) install that in-tree tree is the pre-migration venv — built by whichever interpreter created it — so it was prepended ahead of the committed generation and its compiled modules shadowed the correct ones.

Related Issue

Behavioural regression on PM-migrated Windows installs (no issue filed; described below).

Observed before the fix

• ModuleNotFoundError: No module named 'pydantic_core._pydantic_core' importing from the pre-PM tree, surfacing as:
  gateway.run: Supervised task hosted_room_worker died 5 times in rapid succession (each within 300s of restart) - giving up restarts
• pywin32 was also loaded from the stale tree and failed: ImportError: DLL load failed while importing _win32sysloader.
• The gateway's PYTHONPATH/VIRTUAL_ENV pointed at <repo>/venv (a 3.11 tree) even though the process runs the 3.14 store Python with a committed 3.14 generation available.

Root cause: the helper returns after the first candidate whose Lib/site-packages exists, and that candidate was the hardcoded <repo>/venv.

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)

Changes Made

• gateway/run.py: _ensure_windows_gateway_venv_imports() now resolves the committed generation via pm.environments.committed_venv(project_root) and uses it as the candidate. It falls back to the in-tree venv/ only when PM has no committed generation (legacy installs), preserving existing behaviour for pre-PM trees. Failure to import PM degrades to the old path.
• tests/gateway/test_windows_gateway_venv_imports.py: @pytest.mark.platforms("windows") regression test asserting the committed venv becomes VIRTUAL_ENV, reaches sys.path, has addsitedir semantics applied (a .pth entry is processed — pywin32 needs this), and is advertised in PYTHONPATH.

The test is red on the previous code (it selects <repo>/venv) and green with the fix.

How to Test

1. On Windows, from a PM-migrated install: scripts/run_tests.sh tests/gateway/test_windows_gateway_venv_imports.py.
   • With the fix: passes.
   • On the previous code: fails, because VIRTUAL_ENV ends up as <repo>/venv instead of the injected committed generation.
2. Manual: restart the gateway and confirm PYTHONPATH / VIRTUAL_ENV point at the PM generation, and that gateway.log no longer shows hosted_room_worker dying with a pydantic_core._pydantic_core ModuleNotFoundError. pywintypes then resolves to the PM environment's pywin32_system32\pywintypes314.dll.

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 the tests per the repo rule (scripts/run_tests.sh, not bare pytest) for the affected file, plus ruff check and python scripts/check-windows-footguns.py --all
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform: Windows 11 (Python 3.14.7, PM-managed generation)

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) - or N/A (code comment added explaining the PM preference)
• 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 - the change is inside a sys.platform == "win32" early-return helper, so non-Windows behaviour is untouched
• I've updated tool descriptions/schemas if I changed tool behavior - or N/A

Screenshots / Logs

Live verification on the affected Windows host (PID values redacted):

• New gateway after the fix: PYTHONPATH = <repo> ; <pm>\Lib\site-packages ; <repo> ; <pm>\Lib\site-packages (PM env only — the pre-PM tree is gone), VIRTUAL_ENV = <pm>.
• import pywintypes → <pm>\Lib\site-packages\pywin32_system32\pywintypes314.dll
• import pydantic_core._pydantic_core → <pm>\Lib\site-packages\pydantic_core\_pydantic_core.cp314-win_amd64.pyd
• gateway.log: last ERROR predates the fix; zero ERROR lines after the restart.
• GET /health → 200 {"status":"ok","platform":"hermes-agent","version":"0.21.5"}

[Bifras]

Closing as a duplicate: same fix as #122768, #123149, #123550 and #122805 for issue #122183. Leaving it to the existing PRs to avoid adding noise. (Unique evidence kept: cp311 pywin32 in the pre-PM in-tree venv fails to load under the 3.14 store Python -> ImportError: DLL load failed while importing _win32sysloader.)