GET a repository's commits answers `{ items, next_cursor }`, and every test that reads it is updated #5083

The commit log answers a bare array; the list shape in src/http/api.ts is { items, next_cursor } (see #5062, whose test allowlists this route until this lands).

Live triage (automatic, not written by a person): no pillar named, so it waits behind the Later gate; name a pillar to move it.

Parked by the crew: the check failed ("a plan of 2,000 closed and 300 open issues, 3,000 pulls and 1,500 runs reads in under 50 ms with the same limbs") and the decider saw no point in another try (pull #5087 closed). Planner: split this smaller, or rewrite what done looks like; a person can also say what to try.