feat: reject contradictory reviewer handoff ledgers (Closes #501)

Add reviewer_handoff_consistency validation for narrative vs mutation
ledger contradictions, wire it into review_pr final-report rules, and
document the blocked-review handoff template.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

docs/llm-workflow-runbooks.md

@@ -821,6 +821,7 @@ scripts/release-tag v0.4.0 --notes-file /tmp/release-notes.md --push
 
 ## Related documents
 
+- [`reviewer-handoff-consistency.md`](reviewer-handoff-consistency.md) — reject contradictory reviewer handoffs (#501).
 - [`../skills/llm-project-workflow/SKILL.md`](../skills/llm-project-workflow/SKILL.md) — portable cross-project LLM workflow skill.
 - [`gitea-execution-profiles.md`](gitea-execution-profiles.md) — the profile model.
 - [`gitea-dual-namespace-deployment.md`](gitea-dual-namespace-deployment.md) — static author/reviewer namespace deployment (#139 decision).

docs/reviewer-handoff-consistency.md

@@ -0,0 +1,35 @@
+# Reviewer Handoff Consistency
+
+Reviewer and final-review controller handoffs must not contradict themselves.
+A narrative that says a merge happened, a review was blocked, or a terminal
+mutation budget was consumed must match the mutation ledger fields in the same
+handoff.
+
+## What gets validated
+
+`reviewer_handoff_consistency.assess_reviewer_handoff_consistency()` checks:
+
+- merge claims appear under `Merge mutations` or `MCP/Gitea mutations`
+- terminal-mutation-budget claims name the exact prior mutation in the ledger
+- blocked review submission is not paired with "final decision marked"
+- reviewer lease acquisition includes a `Review decision`
+- blocked/rejected mutations include proof fields:
+  - tool called
+  - mutation attempted
+  - mutation rejected
+  - no server-side state changed
+
+`final_report_validator` applies this as `reviewer.handoff_consistency` on
+`review_pr` reports and fails closed.
+
+## Blocked review template
+
+When `gitea_submit_pr_review` fails closed, use
+`reviewer_handoff_consistency.render_blocked_review_handoff_template()` or the
+copy in
+[`skills/llm-project-workflow/templates/blocked-review-handoff.md`](../skills/llm-project-workflow/templates/blocked-review-handoff.md).
+
+## Related
+
+- #331 — file-mutation ledger alignment
+- #501 — contradictory narrative vs ledger detection