fix: preserve reverse migration record hashes

hub_core/runtime/migration.py

@@ -413,7 +413,7 @@ async def export_bundle(store: PostgresPortStore, *, source_revision: str | None
         "apiConsumers": [_body(row, created=True) for row in consumers],
         "apiKeys": [{"id": row["id"], "apiConsumerId": row["api_consumer_id"], "keyPrefix": row["key_prefix"], "keyHash": row["key_hash"], "scopes": row["scopes"], "status": row["status"], "createdAt": _timestamp(row["created_at"])} for row in keys],
         "widgets": [_body(row, created=True) for row in widgets],
-        "interactionEvents": [{**dict((row["payload"] or {}).get("legacy") or {}), "id": row["id"], "widgetId": (row["subject_refs"] or {}).get("widget"), "eventType": row["event_type"], "occurredAt": _timestamp(row["occurred_at"]), "recordedAt": _timestamp(row["recorded_at"]), "correlationId": row["correlation_id"]} for row in events],
+        "interactionEvents": [_export_interaction(row) for row in events],
         "migrationRuns": [{"id": row["id"], "source": row["source"], "schemaVersion": row["schema_version"], "bundleSha256": row["bundle_sha256"], "dryRun": row["dry_run"], "status": row["status"], "counts": row["counts"], "diagnostics": row["diagnostics"], "createdAt": _timestamp(row["created_at"])} for row in runs],
     }
     high_water = max((_timestamp(row["recorded_at"]) for row in events), default=None)
@@ -424,8 +424,32 @@ async def export_bundle(store: PostgresPortStore, *, source_revision: str | None
     return bundle
 
 
+def _export_interaction(row: Any) -> dict[str, Any]:
+    legacy = dict((row["payload"] or {}).get("legacy") or {})
+    if legacy:
+        # Imported records retain their exact source representation so reverse
+        # export is a lossless rollback artifact, including optional timestamp
+        # and correlation fields that were absent in the source.
+        return legacy
+    return {
+        "id": row["id"],
+        "widgetId": (row["subject_refs"] or {}).get("widget"),
+        "eventType": row["event_type"],
+        "occurredAt": _timestamp(row["occurred_at"]),
+        "recordedAt": _timestamp(row["recorded_at"]),
+        "correlationId": row["correlation_id"],
+        "metadata": row["payload"],
+    }
+
+
 def _body(row: Any, *, created: bool = False, updated: bool = False) -> dict[str, Any]:
     value = dict(row["body"] or {})
+    if value.get("id") == row["id"]:
+        # Import stores the complete source record as its body. Returning that
+        # record verbatim keeps reverse export hash- and field-exact; records
+        # created natively lack the generated database identity and are enriched
+        # from their columns below.
+        return value
     if created:
         value["createdAt"] = _timestamp(row["created_at"])
     if updated: