feat(campaign): govern attachment reuse

tests/test_campaign_build_recovery.py

@@ -16,8 +16,10 @@ from govoplan_campaign.backend.persistence.campaigns import (
     _verify_storage_keys_absent,
 )
 from govoplan_campaign.backend.routes.versions import (
+    _attachment_reuse_audit_evidence,
     _campaign_build_recovery_plan,
     _residual_file_audit_evidence,
+    _review_decision_audit_evidence,
 )
 
 
@@ -56,6 +58,49 @@ def test_residual_file_audit_evidence_omits_recipient_identity() -> None:
     }
 
 
+def test_attachment_reuse_audit_evidence_keeps_policy_but_not_file_names() -> None:
+    assert _attachment_reuse_audit_evidence({
+        "contract_version": "1",
+        "policy": {"action": "review", "allow_within": "same_recipient"},
+        "duplicate_file_count": 4,
+        "allowed_file_count": 1,
+        "violation_file_count": 3,
+        "affected_message_count": 5,
+        "findings": [{"file_name": "personal.pdf"}],
+    }) == {
+        "contract_version": "1",
+        "policy": {"action": "review", "allow_within": "same_recipient"},
+        "duplicate_file_count": 4,
+        "allowed_file_count": 1,
+        "violation_file_count": 3,
+        "affected_message_count": 5,
+    }
+
+
+def test_review_decision_audit_evidence_is_aggregate_and_integrity_sealed() -> None:
+    version = type("Version", (), {
+        "editor_state": {
+            "review_send": {
+                "issue_decisions": [{
+                    "decision": "accept",
+                    "reason": "Approved exception",
+                    "issue_codes": ["duplicate_attachment_reuse"],
+                    "issue_fingerprint": "f" * 64,
+                    "message_sha256": "m" * 64,
+                }]
+            }
+        }
+    })()
+
+    evidence = _review_decision_audit_evidence(version)
+
+    assert evidence["count"] == 1
+    assert evidence["with_reason_count"] == 1
+    assert evidence["issue_codes"] == ["duplicate_attachment_reuse"]
+    assert len(str(evidence["evidence_sha256"])) == 64
+    assert "Approved exception" not in str(evidence)
+
+
 def test_generated_object_manifest_verifies_exact_bytes(tmp_path: Path) -> None:
     storage = LocalFilesystemStorageBackend(tmp_path)
     payload = b"Message-ID: <build@example.test>\r\n\r\nbody"