verify-findings

Dispatch and collect the finding-verifier fleet at stage_23_verify_findings (PLN-722). Reads verify_manifest.json (written by stage_22b_verify_prepare), spawns one falsify-oriented verifier Task per to_verify[] entry with mode-specific Task scheduling (GitHub mode dispatches verifiers synchronously; local mode uses parallel background + blocking TaskOutput), skips cache_hits[], and collects outputs without retry — missing outputs degrade to pending_verification[] (and, in GitHub mode, a missing BLOCKING/HIGH verifier raises a coverage-gap signal). Invoke when the walker reaches stage_23_verify_findings. Do NOT use for the reviewer fleet (stage_20 — see the spawn-reviewers skill) or the PLN-725 singletons (stage_11/stage_15 — see the singleton-dispatch skill).