Crew launch retries converge on the final approved roster #220

A Crew launch that fails partway is supposed to hand the gate back and let a retry converge on the same seats. Three retry paths do not converge today, and each one either strands a seat or refuses a seat the person approved.

Where it breaks:

• Addition retries never clean up stale reservations. CrewLaunchService.addSeats (apps/server/src/j5/a2a/CrewLaunchService.ts:702-766) reserves member rows before spawning but, unlike the initial-roster path (:639-674), never retires a reservation the person renamed or dropped on the retry. Rename old-name to new-name after a failed addition and the Crew ends up with both rows, one never briefed, and the dead row counts against the twelve-seat cap.
• A seat dropped on one retry and re-added on the next is refused as retired. assertReusableSeats (CrewLaunchService.ts:586-596) sees that the deterministic seat thread was archived by the earlier retry cleanup and refuses with "reusing a retired seat". Nothing can ever launch that seat name for that proposal again. The 2026-09-18 worklog left this open; I want it closed.
• A persona change on an uncreated seat is silently lost. AgentCrewInstanceService.ts:202 inserts members with INSERT OR IGNORE, so if the person changes a not-yet-spawned seat's persona or reason before retrying, the manifest keeps the old values while the seat launches with the new ones.

What should change:

• Before spawning, reconcile this proposal's reservations against the final approved roster: retire reservations for seats that were dropped or renamed, update persona and reason on reservations whose thread does not exist yet, and never touch a seat whose thread already exists.
• For a re-added seat whose deterministic thread was archived by a previous retry, unarchive that thread and reuse it rather than minting a new id. My call is to keep every id derivable from proposal and seat name; if that turns out to be impossible, say so on this issue before switching to a fresh id.
• Apply the same convergence to roster launches and additions through one code path.

Tests to ship (CrewLaunchService.test.ts, AgentCrewInstanceService.test.ts):

• failed addition, then rename at eleven existing seats, converges without hitting the cap
• drop a seat on one failed launch, re-add it on the next, and the seat is briefed exactly once
• change an uncreated seat's persona before retry and the manifest reflects the new persona
• established seats and their threads are untouched by a retry

Done when a retry after any failed launch or addition lands the exact roster the person approved on the last card, with no orphan rows and no "retired seat" refusal for a seat that is on that roster.

Related criteria: crews.md AC7.

Blocks (soft) #222. The cap counting there is simpler once stale reservations from failed retries are gone. Independent of #221, though both touch the launch recovery path; land whichever is ready and rebase the other.