fix(tar): `tar -c` cannot stat files on VFS

[chaliy]

Summary

tar -c -z -f archive.tar.gz file.txt fails with Cannot stat: No such file or directory when operating on VFS files, even though the files exist and can be read by cat.

Reproduction

echo "content" > /tmp/test.txt
cat /tmp/test.txt   # works fine
tar -c -z -f /tmp/test.tar.gz -C /tmp test.txt
# Error: tar: test.txt: Cannot stat: No such file or directory
ls /tmp/test.tar.gz
# Error: cannot access: No such file or directory

Context

Discovered while running bashblog via bashkit CLI. Bashblog creates backups before rebuilding:

tar -c -z -f ".backup.tar.gz" -- *.html
chmod 600 ".backup.tar.gz"

This fails silently, so no backups are created during the rebuild process.

Expected behavior

tar -c should be able to stat and archive files that exist on the VFS. The -C directory change should also work with VFS paths.