feat(campaign): govern attachment reuse

src/govoplan_campaign/backend/routes/versions.py

@@ -594,6 +594,7 @@ def set_version_review_state(
                 "inspection_complete": payload.inspection_complete,
                 "reviewed_message_count": len(payload.reviewed_message_keys),
                 "issue_decision_count": len(payload.issue_decisions),
+                "issue_decisions": _review_decision_audit_evidence(version),
             },
             commit=True,
         )
@@ -879,6 +880,9 @@ def build_version(
                 "residual_file_disposition": _residual_file_audit_evidence(
                     result.get("residual_file_disposition")
                 ),
+                "attachment_reuse": _attachment_reuse_audit_evidence(
+                    result.get("attachment_reuse")
+                ),
             },
             commit=True,
         )
@@ -925,3 +929,54 @@ def _residual_file_audit_evidence(value: object) -> dict[str, object]:
             "residual_file_count",
         )
     }
+
+
+def _attachment_reuse_audit_evidence(value: object) -> dict[str, object]:
+    if not isinstance(value, dict):
+        return {}
+    policy = value.get("policy")
+    return {
+        "contract_version": value.get("contract_version"),
+        "policy": dict(policy) if isinstance(policy, dict) else {},
+        "duplicate_file_count": value.get("duplicate_file_count"),
+        "allowed_file_count": value.get("allowed_file_count"),
+        "violation_file_count": value.get("violation_file_count"),
+        "affected_message_count": value.get("affected_message_count"),
+    }
+
+
+def _review_decision_audit_evidence(
+    version: CampaignVersion,
+) -> dict[str, object]:
+    editor_state = version.editor_state if isinstance(version.editor_state, dict) else {}
+    review_state = editor_state.get("review_send")
+    if not isinstance(review_state, dict):
+        return {}
+    raw_decisions = review_state.get("issue_decisions")
+    decisions = [item for item in raw_decisions or [] if isinstance(item, dict)]
+    evidence = [
+        {
+            "decision": item.get("decision"),
+            "issue_codes": sorted(
+                str(code) for code in item.get("issue_codes") or [] if code
+            ),
+            "issue_fingerprint": item.get("issue_fingerprint"),
+            "message_sha256": item.get("message_sha256"),
+            "reason_recorded": bool(str(item.get("reason") or "").strip()),
+        }
+        for item in decisions
+    ]
+    return {
+        "count": len(evidence),
+        "with_reason_count": sum(
+            1 for item in evidence if item["reason_recorded"]
+        ),
+        "issue_codes": sorted(
+            {
+                code
+                for item in evidence
+                for code in item["issue_codes"]
+            }
+        ),
+        "evidence_sha256": _canonical_sha256(evidence),
+    }