0190 — Reclaim is one atomic UPDATE, not DELETE plus INSERT

Context. Reclaim was originally a DELETE of the expired lease followed by a fresh INSERT. With the new lease.reclaims counter, that shape silently reset the counter to 0 on every reclaim — the exact value the repeated-reclaim cap depends on.

Decision. Reclaim is a single atomic UPDATE on the lease row: reclaims = reclaims + 1, token rotated, until refreshed.

Consequences. The counter survives across reclaims, making MaxRangeReclaims (see 0191) enforceable at all; token rotation — the guard that lets CommitRange from a superseded worker no-op — is preserved explicitly rather than falling out of a row replacement. Supersedes the delete-then-insert shape from the original reclaim implementation.