Enforce single terminal review decision per PR review run (Issue #211)

Reviewer agents could post probe APPROVE/REQUEST_CHANGES reviews while
testing lock paths, polluting PR audit trails. Add a review decision lock
seeded by gitea_resolve_task_capability(review_pr) that requires
gitea_mark_final_review_decision and final_review_decision_ready=True
before gitea_submit_pr_review performs a live mutation.

Add gitea_dry_run_pr_review for read-only submission validation,
gitea_authorize_review_correction for operator-approved fixes, and
assess_review_mutation_final_report for final-report proof. One live
review mutation per run unless correction is explicitly authorized.

review_proofs.py

@@ -582,6 +582,54 @@ def assess_role_boundary(proof=None, *, task_role=None, namespaces_used=None,
     }
 
 
+def assess_review_mutation_final_report(report_text, review_decision_lock):
+    """Require final reports to list exactly one live review mutation.
+
+    Two mutations are allowed only when an operator-approved correction flow
+    was invoked and explained in the report.
+    """
+    lock = review_decision_lock or {}
+    text = report_text or ""
+    lower = text.lower()
+    mutations = list(lock.get("live_mutations") or [])
+    missing = []
+
+    count = len(mutations)
+    if count == 0:
+        if any(term in lower for term in ("submitted 'approve'", "submitted 'request_changes'", "live review mutation")):
+            missing.append("review mutation count")
+    elif count == 1:
+        m = mutations[0]
+        action = m.get("action")
+        pr_number = m.get("pr_number")
+        if action and action.lower() not in lower:
+            missing.append("review mutation action")
+        if pr_number is not None and f"#{pr_number}" not in lower and f"pr {pr_number}" not in lower:
+            missing.append("review mutation PR number")
+    elif count > 1:
+        if not lock.get("correction_authorized") and "correction" not in lower:
+            missing.append("correction flow explanation")
+        if "review mutations:" not in lower and "review mutation" not in lower:
+            missing.append("review mutation listing")
+
+    if missing:
+        return {
+            "complete": False,
+            "downgraded": True,
+            "missing_fields": missing,
+            "reasons": [
+                f"final report missing review-mutation field: {field}"
+                for field in missing
+            ],
+        }
+    return {
+        "complete": True,
+        "downgraded": False,
+        "missing_fields": [],
+        "reasons": [],
+    }
+
+
 def build_final_report(checkout_proof, inventory, validation, contamination,
                        identity_eligible, merge_performed,
                        issue_status_verified,