Fix #2981: Add Windows platform guard for SIGALRM in timeout_decorator and card_cli

[k-kj0]

Fixes #2981

Added sys.platform == "win32" guards to:

• metaflow/plugins/timeout_decorator.py
• metaflow/plugins/cards/card_cli.py

Both files used signal.SIGALRM which is POSIX-only and crashes on Windows.
This implements Option B from the issue: a clear early error instead of a
cryptic AttributeError mid-run.

[greptile-apps]

Greptile Summary

This PR adds sys.platform == "win32" guards to both timeout_decorator.py and card_cli.py to prevent a cryptic AttributeError when signal.SIGALRM is used on Windows. The import sys statement is correctly placed at the module level in both files, and the guard blocks are properly indented inside their respective function bodies — the issues flagged in previous review threads are fully resolved.

Confidence Score: 5/5

This PR is safe to merge — it adds simple, correct Windows guards with no logic changes to existing POSIX paths.

Both files have correct module-level imports, proper indentation, and the guard fires before any SIGALRM call. The task execution flow confirms task_post_step (which calls signal.alarm(0)) is unreachable on Windows after the guard raises in task_pre_step. No P0/P1 issues found.

No files require special attention.

Important Files Changed

Filename	Overview
metaflow/plugins/timeout_decorator.py	Adds import sys at module level and a Windows guard in task_pre_step before SIGALRM calls; indentation and placement are correct.
metaflow/plugins/cards/card_cli.py	Adds import sys at module level and a Windows guard at the top of the timeout() context manager before signal calls; indentation and placement are correct.

_{Reviews (3): Last reviewed commit: "Update card_cli.py" | Re-trigger Greptile}