The virtual engine now detects local members (repo_type=local) and
generates their package index in-memory instead of trying to fetch
from a non-existent upstream.
- MemberIndex gains RepoType field so mergers use correct URL prefix
(/api/v1/local/ vs /api/v1/remote/)
- Virtual engine accepts a LocalIndexGenerator interface for producing
local PyPI indexes
- LocalHandler implements GeneratePyPIPackageHTML for reuse by both
the direct serving path and the virtual merger
- Includes local PyPI upload support (cherry-picked from benvin/local-pypi)
Tested e2e: local wheel upload + virtual merge + uv pip install from
both direct local and virtual URLs
unkinben