fix(cron): pass shell scripts to bash with POSIX paths

[BROCCOLO1D]

Summary

• Fixes .sh/.bash cron script execution on Windows by passing Git Bash a forward-slash script path.
• Closes Bug: .sh cron scripts fail on Windows - bash receives mangled backslash paths #43073.

Why

• str(Path(...)) produces backslash-separated Windows paths.
• Bash treats those backslashes as escapes, so paths like C:\Users\...\cron-watchdog.sh are mangled before execution.

Changes

• cron/scheduler.py: formats bash script argv paths via Path.as_posix() while leaving Python script execution unchanged.
• tests/cron/test_cron_script.py: adds a regression check for Windows path conversion.

Validation

• python -m pytest tests/cron/test_cron_script.py -o 'addopts=' -q
• python -m py_compile cron/scheduler.py
• python -m ruff check cron/scheduler.py tests/cron/test_cron_script.py

Scope

• In scope: .sh/.bash cron script argv path formatting for bash.
• Out of scope: changing cron script path validation or Python script execution.

[BROCCOLO1D]

Closing this as stale: there has been no activity or maintainer follow-up for over a week, and I don't want to leave inactive work open. Happy to reopen/rework if this becomes useful.