Delayed loot-roll START can recreate a resolved roll #441

A delayed Loot Roll START can recreate a roll after its first resolution. PR #439 prevents concurrent promotion from creating two live rows, which satisfies #63. Resolution still removes the row that promotion uses for deduplication.

The current path is:

1. Two Gateways read the same staging roll in gateway/src/world/loot.rs::promote_one.
2. Gateway A promotes it. Votes, the deadline sweep, or a group disband resolve it in Realm-core.
3. module/src/loot/rolls.rs::cleanup_roll deletes the roll and its votes.
4. Gateway B sends the START it read earlier. insert_roll_rows finds no row for the corpse and slot and inserts fresh votes.

Choose how to identify a roll across resolution and how long that identity must remain. Creature guids and loot slots can be reused on a later kill, so permanently refusing the same corpse and slot would also prevent valid future rolls. Keeping resolved rows until a timeout only prevents replays within that timeout. Assess a generation identifier or a promotion acknowledgement protocol before choosing storage and cleanup rules. Follow docs/danger-zones.md if the decision changes schema.

Done when a durable integration test resolves a promoted roll, replays its original START, and verifies through SQL that no new active roll or vote set appears. Also prove that a later valid roll on the same corpse and slot can start, and test the chosen cleanup boundary. Keep the existing settlement grant Gate intact.

This was generated by AI during triage.