qstack-make-operations-idempotentlisted

# Make operations idempotent An idempotent operation converges from any state a previous attempt could have left behind. A duplicate request that merely happens not to fail is not enough. ## Test convergence 1. List every durable mutation and external side effect in execution order. 2. Model two consecutive runs from the completed state. When verification is authorized in a safe environment, run both and compare the real end state, not only the exit code. 3. Model a crash after every mutation point and the rerun from each partial state. Fault-inject only under the verification authority described below. 4. Include stale locks, abandoned temporary files, live sessions, regenerated input, reordered records, and content-equivalent artifacts where relevant. 5. Add reconciliation before mutation whenever leftover state changes the next run's result. Prefer adoption, content comparison, atomic replacement, single ownership, and stale-owner detection over creation-order guesses. 6. Prove repeated and resumed runs satisfy the same domain invariants. Generated identifiers or timestamps need not be byte-identical unless the domain requires that. Report the mutation map, failure points tested, stale-state policy, convergence proof, and any unresolved case. Never clear or overwrite user data merely to make a retry pass without explicit authority for that destructive behavior. Before reclaiming a lock or live session, prove ownership and liveness. A design or