fix(cron): use path.as_posix() for .sh scripts on Windows

[franchaise]

On Windows, cron .sh and .bash scripts were passed to bash using str(path), which produced backslash-separated paths. Bash (especially Git Bash / WSL) interprets backslashes as escape characters, so the script path could be mangled and fail to execute.

This change passes path.as_posix() for shell scripts so the argument is a forward-slash path regardless of host OS.

• cron/scheduler.py: use path.as_posix() when invoking .sh/.bash scripts
• tests/cron/test_cron_no_agent.py: add regression test test_run_job_script_sh_uses_posix_paths

Closes #43073

[alt-glitch]

Duplicate of #23405 — identical one-line fix using path.as_posix() for .sh/.bash script paths on Windows so Git Bash doesn't mangle backslashes. #23405 (open) is the earliest; #23489 and #43076 take the same approach.

[teknium1]

Thanks for the focused Windows cron fix. The production hunk addresses a defect still present on current main: cron/scheduler.py:2092 passes str(path) to bash for .sh/.bash scripts.

Problems

• The proposed regression assertion cannot fail on a POSIX host. hermes_env creates a host-native Path (tests/cron/test_cron_no_agent.py:21), so its argument already has / before this change; the added assertions at lines 366-367 of the PR diff therefore pass with the old str(path) implementation.
• The linked #46332 reports a separate Windows failure: current cron/scheduler.py:2083 still uses shutil.which("bash"), which can select the WSL launcher ahead of Git Bash. This PR fixes path formatting but not that resolver case.

Suggested changes

• Make the path-format regression meaningful on native Windows, using an actual Windows Path and a captured subprocess argv; skip outside win32 unless extracting a testable cross-platform helper.
• Keep Git-Bash-versus-WSL selection as a focused follow-up for #46332.

Automated hermes-sweeper review.

[teknium1]

On a POSIX runner, script_path is already a Path with / separators, so this assertion also passes before the production change. Please make this a native-Windows regression using a real Windows path (or extract and test a platform-independent conversion helper).

[andrexibiza]

Reconciliation (2026-08-03): this PR's change (path.as_posix() for .sh scripts on Windows) is the Layer-2 path half, now canonical in #77393 (fix(cron): pass Git-Bash-safe script path to bash on Windows — all CI checks green, mergeable_state: CLEAN), which uses the established _bash_safe_path MSYS convention, also fixes the sibling tools/approval.py hint, and adds regression tests + docs. This branch is conflicting against main with no CI checks reported. Recommend closing as a duplicate of #77393.