#3314 Windows-built extension tarballs have 0666 directories; registry scorer can't find manifest.yaml

Summary

On Windows, swamp extension push / swamp extension quality build extension.tar.gz with every directory entry marked mode 0666 (drw-rw-rw-), so directories have no execute bit. When the registry scorer extracts the archive on Linux as a non-root user, it can list extension/ but can't open anything inside it. Scoring fails with:

No manifest.yaml found in tarball (searched up to 2 directory levels)

The manifest is there (extension/manifest.yaml). Local swamp extension quality passes (100%) because Windows ignores the mode bits.

Steps to reproduce

1. On Windows, run swamp extension quality manifest.yaml (or push) for any extension (seen with @gluware/nib-concepts@2026.10.12.2, a skills-only extension).
2. tar tvzf .swamp/cache/packages/<hash>/extension.tar.gz. All directories show as drw-rw-rw- 0/0.
3. Extract on Linux as a non-root user:

$ tar xzf extension.tar.gz
$ ls -ld extension
drw-r--r-- 15 user user 4096 ... extension
$ stat extension/manifest.yaml
stat: cannot statx 'extension/manifest.yaml': Permission denied
$ find . -maxdepth 2 -name manifest.yaml
find: './extension/skills': Permission denied   (every subdirectory)

1. Registry page shows "Scoring failed", and refresh rescores the same archive, so it can't recover.

Expected

The packager writes directory entries as 0755 (and files as 0644) regardless of host OS. Alternatively, the scorer normalises permissions on extract.

Environment

• swamp 20261012.175401.0-sha.6de906ec
• Windows 11 Pro 10.0.26300
• Scorer behaviour reproduced with GNU tar on Ubuntu (WSL), non-root