fix(script): silence git rm --cached stdout to prevent JSON corruption

[hilram7]

Root cause

When the workflow checks out the PR head branch, the files without .md are tracked in the git index. git rm --cached succeeds and prints rm 'filename' to stdout, which gets captured in the SUMMARY variable and corrupts the JSON, causing jq to fail with exit code 5.

Previously undetected because the workflow checked out the base branch (dev), where the PR files aren't tracked — git rm --cached failed silently with no stdout output.

Fix

Add -q to silence git rm --cached stdout.

Testing

Tested locally by simulating the workflow condition: checked out the PR head branch (files tracked in git index), ran the script, confirmed clean JSON output and correctly renames/injects frontmatter.