Bug: manifest preflight compares MSYS and Win32 temp paths literally

[tianmind-studio]

Summary

make preflight cannot complete on native Windows because test_run_checks.py assumes the path passed through Bash has the same string representation as Python's Win32 temporary path.

Reproduction

1. Run the local manifest preflight on Windows.
2. Ensure the subprocess uses Git Bash (the bare bash executable otherwise resolves to C:\Windows\System32\bash.exe/WSL before PATH entries under Windows CreateProcess).
3. RunnerBehaviorTests.test_release_process_guard_uses_locked_pyyaml_in_every_declared_lane reaches its final assertion and fails:

/tmp/tmpXXXX/.github/scripts/check-release-process-guards.py
!=
C:\Users\...\AppData\Local\Temp\tmpXXXX\.github\scripts\check-release-process-guards.py

The command itself succeeds; only the raw path-string comparison at .github/scripts/test_run_checks.py:435 fails. This stops check-manifest-contract, the first always-selected preflight check, so later checks never run.

Expected

The contract test should compare the same logical path across MSYS and Win32 representations (or capture a platform-neutral argument identity), and Windows subprocesses should resolve the intended Git Bash explicitly rather than relying on bare-name executable search.

Evidence

Observed while validating #10823 on Windows 11 with Python 3.11.15 and Git Bash 5.2.15. The other 29 test_run_checks.py cases and all 13 remaining checks selected for that diff passed.

[tianmind-studio]

#10825 now covers both Windows failure layers here: it compares MSYS/Win32 paths by filesystem identity and resolves manifest-leading bash/python3 to Git for Windows Bash/current Python instead of the System32 WSL launcher or an absent executable. On current main, that head plus the related Windows fixture fixes completed the official make preflight with all 30 selected checks passing in 223.41s on native Windows. The PR is green but still awaiting maintainer/workflow review, so this issue should close when it merges.