Problem

No support for shallow clones (--depth N). Every fetch must download the full commit history, which is prohibitive for large repositories.

Impact

• CI systems and deployment scripts can’t do fast shallow clones
• Bandwidth and time wasted downloading irrelevant history
• Common git workflow pattern unsupported

Acceptance Criteria

• Upload-pack supports shallow and deepen capabilities
• Client can request depth-limited history
• Shallow boundary tracked (.git/shallow equivalent)
• Subsequent fetches can deepen or unshallow
• Interop test: git clone --depth 1 works against this server