PageToken

A continuation cursor for reading older entries of a session's transcript.

It is opaque by construction: only the archive read path (within the log package) mints one. A consumer obtains one from a page and hands it back to fetch the previous page, but cannot forge one against an arbitrary file. Its fields pin the cursor to a single resolved file so it can never be applied to a different one:

• offset is a byte position into an append-only file, so it stays valid as the file grows.
• source is the exact transcript path the cursor was minted against. The vendor-then-mirror fallback can change which file a session resolves to between calls (e.g. the vendor tree is pruned mid-paging); when the current resolution no longer matches source, paging fails rather than reading a stale offset against the wrong file.