Ensure independent reviews return concrete evidence or explicit blockers

When requesting a correctness or security review, use a fresh independent, read-only reviewer against the exact current worktree. Require non-empty findings with severity labels, precise file:line evidence, a compact test/evidence summary, and a definitive merge decision. If inspection cannot be completed, require an explicit BLOCKED reason rather than an empty response. When a reviewer returns no evidence or is interrupted, nudge or retry it; after repeated empty results, replace only that reviewer. While the replacement runs, do not edit files, duplicate its work, sleep, poll, or request status.