0191 — A range past MaxRangeReclaims moves into the per-message exception path

Context. A range whose processing crashes the worker gets reclaimed forever (the known handoff left open when leases landed, see 0165). Somewhere the loop has to end, and the messages need individual handling — usually one of them is poison and the rest are fine.

Decision. Once a lease’s reclaims counter passes MaxRangeReclaims, every message in the range is inserted into deliveries as a ready row with a fresh attempt budget, and the lease is deleted for good instead of being handed out again. No range-level dead-letter mechanism was built.

Consequences. Each message gets the same per-message retry/backoff/dead-letter treatment as an ordinary Commit-recorded failure, so AdvanceWaterline needed zero new logic — its blocker term was already generic over any unresolved exception. The range’s healthy messages resolve individually via ClaimExceptions + RecordExceptionSuccess; only the actually-poison one ends at dead. Rejected: dead-lettering at range granularity — a second failure-handling mechanism that would condemn a range’s healthy messages along with the poison one.