Add paginated com.atproto.sync endpoint helpers · Issue #10 · zat.dev/zat

Remaining work #

Add focused helpers over the existing XRPC and HTTP transport APIs for repository enumeration and downloads:

com.atproto.sync.listRepos pagination, including cursor handling and stopping at the final page.
com.atproto.sync.getLatestCommit response decoding.
com.atproto.sync.getRepo download helpers, with a writer-oriented path for callers that do not want to buffer the whole repository. Reuse transport cancellation, deadlines, stall protection, and response limits.

Keep helpers composable with XrpcClient / HttpTransport; avoid introducing a second general-purpose client or retry policy. Verify pagination boundaries, structured endpoint errors, cancellation, and truncated or stalled downloads.

Already available #

CAR parsing, MST traversal, and commit verification are implemented. The walk-a-repo example shows the existing fetch-and-traverse path. HTTP transfer protection lives in zttp.

Scope #

This issue is about the missing endpoint adapters and pagination, not another CAR/MST iterator, transport implementation, or higher-level sync framework.