Claim safety — claim, then prove you own the lease

Chain: once you have PROVEN the lease (forge issue owns <id> exits 0), continue to dev to work the issue (smith proceeds into plan/dev after this proof). Usable standalone whenever ownership is in question.

Claiming is not owning. The Forge kernel keys a claim's idempotency on claim.create:<issue_id>:<actor>, so a same-key duplicate replay returns ok:true echoing the current call's claim_id. A genuine cross-actor conflict returns ok:false (the partial-UNIQUE active-lease index guarantees one lease) — but ok:true alone does not prove sole ownership. A live lease can also be reclaimed on expiry (an expired lease is superseded by the next claimant). Therefore every worker MUST verify ownership before mutating a claimed issue, and RE-verify before close/release.

This is a reusable, standalone procedure: any skill or agent that mutates a claimed issue embeds it (it is NOT folded into one orchestrator).

The verification primitive