uv-configuration-stub

Minimal local stub for the uv-configuration crate from uv, stripped to only the types needed by uv-requirements-txt.

PackageNameSpecifier -- enum for :all:, :none:, or a specific package name
NoBinary -- whether to disallow wheel installations (--no-binary)
NoBuild -- whether to disallow source builds (--only-binary)

These types are used by uv-requirements-txt to parse --no-binary and --only-binary pip arguments. The parsed values are not surfaced to the host — they exist only to satisfy the upstream parser's type requirements.

Based on uv revision 35d1e90.