Fix workflow CWD safety for file locks and git diff logging

[gyx09212214-prog]

Summary

• resolve file:// tracking URIs to local absolute paths before creating the workflow file lock
• skip uncommitted-code logging when the current directory is not a git work tree
• run git diff/status commands without shell=True and capture stderr to avoid noisy startup output
• add focused regression tests for the CWD-sensitive path and git logging behavior

Fixes #2252.

Tests

• .\.venv\Scripts\python -m pytest tests\test_workflow_cwd_safety.py -q

Attempted:

• .\.venv\Scripts\python -m pytest tests\test_workflow.py tests\test_workflow_cwd_safety.py -q
  • blocked during collection because this local shallow clone/test env does not have compiled qlib.data._libs.rolling

[gyx09212214-prog]

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