uv-client-stub

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

• Connectivity -- enum (Online / Offline) for network mode selection
• BaseClientBuilder -- builder struct that carries a Connectivity value

Everything else (HTTP client, retry logic, authentication, caching, etc.) has been removed. WASM always runs offline.

Based on uv revision 35d1e90.

Copyright (c) Astral Software Inc. Licensed under Apache-2.0 OR MIT.