CLI: lowercase cvs paths rejected in prebuilt file maps (#17686)

https://github.com/vercel/vercel/issues/17686

`vercel deploy --prebuilt` fails with PREBUILT_FILEPATHMAP_VCS when a route folder is named `cvs` (case-insensitive match on `CVS`) · Issue #17686 · vercel/vercel

Summary With vercel@62.5.0 (and, from the code, any version since 62.4.0), vercel deploy --prebuilt rejects our build with: Error: Prebuilt functions reference version-control files that cannot be ...

Hi CLI team, Before opening a PR, I’d appreciate feedback on my proposed fix for #17686.

Problem

Ordinary lowercase cvs paths in a prebuilt filePathMap are rejected as CVS metadata. Actual CVS metadata paths should still be filtered.

Reference

Issue: https://github.com/vercel/vercel/issues/17686

Proposed Fix

I’ve made the CVS metadata check more precise and added regression tests. The focused client tests (49/49), client type-check, and repository lint pass.

Branch: https://github.com/Harshitr03/vercel/tree/fix-cvs-path-validation

Would this approach fit the CLI’s intended behavior? Thanks!