The boards list and the caller's board pins answer `{ items, next_cursor }` #5045

Intent: a client reads every list the same way; today these answer a bare array.

Done:

• [ ] GET /api/v1/boards and GET /api/v1/boards/pins answer { items, next_cursor } as the header of src/http/api.ts promises for lists, with limit (default 50, max 200) and cursor validated like the issue list's, and a bad limit a 422
• [ ] tests for each: the shape, paging with limit and next_cursor to the end, and a bad limit refused
• [ ] every caller in src/ (the terminal UI, client.ts, mcp.ts, pages) and test/ that read the bare array reads items; the pull says the shape changed

Keep each route's permission and filter exactly as they are; only the shape changes. Other issues change other lists in src/http/api.ts in parallel, so touch only the routes named here.

Parked by the crew: the check failed ("a green agent pull and its reviewer > before the review it is the crew's: no ask, no count, a waiting word") and the decider saw no point in another try (pull #5053 closed). Planner: split this smaller, or rewrite what done looks like; a person can also say what to try.

Parked by the crew: the check failed ("a green agent pull and its reviewer > before the review it is the crew's: no ask, no count, a waiting word") and the decider saw no point in another try (pull #5163 closed).

Parked twice since a person last spoke here, so it is the planner's now. Every reason:

1. the check failed ("a green agent pull and its reviewer > before the review it is the crew's: no ask, no count, a waiting word") and the decider saw no point in another try (pull #5053 closed)
2. the check failed ("a green agent pull and its reviewer > before the review it is the crew's: no ask, no count, a waiting word") and the decider saw no point in another try (pull #5163 closed)

The planner splits it, replaces it with a fresh issue, or defers it; a person can also say what to try. Nothing starts here until then, and the board lists it.

Replaced by #5215: same scope, but it waits for a fix to the unrelated reviewer test that failed both tries (#5160).

Closed as dropped, not split: the forge refused a one-for-one split here. Nothing is lost. #5215 carries this scope word for word, under the same pillar, and waits for the fixes to the unrelated red tests.