feat(data-safety): scheduled DB backups + audit trail + verified actor attribution

- db-backup sidecar: pg_dump -Fc of procurement+casdoor every
  BACKUP_INTERVAL_SECONDS into BACKUP_DIR, retention via BACKUP_KEEP_DAYS
- audit_log table (migration.sql + runtime ensure_audit_table) with
  model + transactional helper (utils/audit.record) — wired into user
  create/role-change and inventory transaction creation
- get_actor: quote_events.actor now stores the VERIFIED user's display
  name instead of the raw bearer token

backend/app/routers/inventory.py

@@ -43,6 +43,7 @@ from app.utils.errors import (
     UnauthorizedError,
     ValidationError,
 )
+from app.utils.audit import record as audit_record
 from app.utils.pagination import paginate, sort_query
 from app.utils.serialization import to_iso
 
@@ -494,6 +495,16 @@ async def create_transaction(
             if dest.project_id != scope.project_id:
                 raise ForbiddenError("انبار مقصد متعلق به پروژه شما نیست")
         txs = await apply_transaction(db, payload, performed_by=scope.actor)
+        await audit_record(
+            db,
+            actor=scope.actor,
+            action="inventory.transaction_created",
+            entity="inventory",
+            entity_id=str(txs[0].inventory_id) if txs else None,
+            details={"type": payload.transaction_type, "quantity": str(payload.quantity),
+                     "warehouse_id": str(payload.warehouse_id),
+                     "tx_ids": [str(tx.id) for tx in txs]},
+        )
     return {"data": [transaction_to_dict(tx) for tx in txs]}