[L03] Queue and GHES evidence

[yunseo-kim]

Scope

Execute the ADR 0075 overflow spike in an isolated repository and record github.com/GHES evidence.

Contracts

ADR 0075 standing items

Dependencies

F03

Blocking issues: [F03] #10.

Executable QA

Dispatch 102 contenders: `for i in $(seq 1 102); do gh workflow run mutation-queue-spike.yml --repo "$CONFORMANCE_REPO" -f contender="$i" -f hold_seconds=300; done`. Then `gh run list --repo "$CONFORMANCE_REPO" --workflow mutation-queue-spike.yml --limit 110 --json databaseId,status,conclusion,createdAt,event > queue-runs.json`. Pass only if one running segment, the documented pending bound, and the overflow run’s rejection/cancellation surface match F03 evidence. `go run ./cmd/slsa-builder-internal fixture-check --fixture testdata/platform/contracts/mutation-queue-overflow.json` must exit 0. Any mismatch is `NO-GO` and requires ADR/spec revision.