feat: classify already-landed PRs as reconciliation-only (Closes #295)

Add reviewer_already_landed_classification verifier to block oldest/next
eligible PR wording, review-eligible claims, and pinned reviewed head
usage when a PR is already landed. Wire the check into build_final_report
and tighten final_report_validator regex coverage.

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

review_proofs.py

@@ -1505,6 +1505,17 @@ def build_final_report(checkout_proof, inventory, validation, contamination,
             "reasons": [],
             "violations": [],
         }
+    if report_text:
+        already_landed_classification = assess_already_landed_classification_report(
+            report_text
+        )
+    else:
+        already_landed_classification = {
+            "proven": True,
+            "block": False,
+            "reasons": [],
+            "violations": [],
+        }
 
     contamination_status = contamination.get("status", "unknown")
     checkout_proven = bool(checkout_proof.get("proven"))
@@ -1659,6 +1670,11 @@ def build_final_report(checkout_proof, inventory, validation, contamination,
             "reviewer baseline validation proof missing or failed (#325)"
         )
         downgrade_reasons.extend(baseline_validation.get("reasons", []))
+    if not already_landed_classification.get("proven"):
+        downgrade_reasons.append(
+            "already-landed classification wording missing or invalid (#295)"
+        )
+        downgrade_reasons.extend(already_landed_classification.get("reasons", []))
 
     merge_allowed = (
         identity_eligible
@@ -1751,6 +1767,12 @@ def build_final_report(checkout_proof, inventory, validation, contamination,
         "baseline_validation_violations": list(
             baseline_validation.get("violations") or []
         ),
+        "already_landed_classification_proven": bool(
+            already_landed_classification.get("proven")
+        ),
+        "already_landed_classification_violations": list(
+            already_landed_classification.get("reasons") or []
+        ),
     }
 
 
@@ -4460,6 +4482,15 @@ def assess_merge_simulation_report(report_text, **kwargs):
     return _assess(report_text, **kwargs)
 
 
+def assess_already_landed_classification_report(report_text, **kwargs):
+    """#295: already-landed PRs are reconciliation-only, not review eligible."""
+    from reviewer_already_landed_classification import (
+        assess_already_landed_classification_report as _assess,
+    )
+
+    return _assess(report_text, **kwargs)
+
+
 def assess_prior_blocker_skip_proof(report_text, **kwargs):
     """#318: require live blocker proof before skipping earlier open PRs."""
     from reviewer_blocker_skip import assess_prior_blocker_skip_proof as _assess