test: strengthen model registry coverage audit

[man4ish]

Summary

• Enabled branch coverage.
• Removed four existing production-module coverage exclusions: package/manifest.py, package/validate.py, storage/localfs.py, and storage/base.py.
• Added six focused tests for Hugging Face routes and organization isolation.

Tests

• 6 focused tests passed.
• Full suite contains 568 collected tests but cannot complete in the current environment.

Environment blocker

A standalone FastAPI TestClient reproduces the same hang outside the repository. The lower-level AnyIO blocking portal also reproduces the problem, while asyncio.run() and anyio.run() work normally. Therefore the blocker is below the repository application/test code.

Environment:

• Python 3.13.9
• pytest 9.0.2
• pytest-asyncio 1.3.0
• FastAPI 0.128.0
• Starlette 0.49.3
• httpx 0.28.1
• AnyIO 4.10.0

Coverage

Baseline: 98.44% line coverage from the existing artifact.

Final coverage: Not available because the complete suite cannot finish. The baseline percentage is not reported as final coverage.

Production protection

Production source files modified: 0.

Pre-existing changes

The generated Cython files were pre-existing user changes and were preserved.

Final status

PASS WITH CONDITIONS / ENVIRONMENT BLOCKED

The repository testing changes are valid, but complete verification requires a supported runtime/environment where the AnyIO/Starlette TestClient blocking portal operates correctly.