R-1253 (P2): an export that stops its app refuses while another operation (a restore) holds the app-stop marker — its Undo is never replaced. Commit only.

controller/scripts/i18n_go_keys.json

@@ -12,6 +12,7 @@
     "err.backup.restore_failed_held_mixed": "BORN AS A KEY (R-893, 2026-10-08, security review) -- a restore that stopped half-way (placement, volume replay or DB start failed) after files/volumes/version had moved; the app is HELD. Pinned by internal/backup/r893_mixed_restore_test.go.",
     "note.restore.interrupted_put_back_waiting": "BORN AS A KEY (R-1251, 2026-10-24) -- the restore record sentence for an interrupted restore whose put-back waits for the app's drive. Never a Go literal; pinned by TestR1251_TheRecordSaysThePutBackWaits.",
     "note.tier2.settings_unreadable_kept": "BORN AS A KEY (R-1252, 2026-10-24) -- the second-drive status note when a rejected backup block made the night copy keep every copy. Never a Go literal; pinned by r1252_rejected_block_keeps_copies_test.go.",
+    "err.appexport.another_operation_running": "BORN AS A KEY (R-1253, 2026-10-24) -- an export that stops its app is refused while another operation holds the app-stop marker. Never a Go literal; pinned by TestR1253_AnExportNeverReplacesARestoresMarker.",
     "hold.putback_pending": "BORN AS A KEY (R-1251, 2026-10-24) -- the hold sentence for an app whose cut restore waits for its drive before its pre-restore data is put back (HoldReasonPutBackPending). Never a Go literal; pinned by internal/backup/r1251_putback_waits_test.go.",
     "note.reconstitute.held_mixed": "BORN AS A KEY (R-893, 2026-10-08) -- the hold sentence for that held app (HoldReasonRestoreMixed). Never a Go literal; pinned by internal/backup/r893_mixed_restore_test.go.",
     "recovery.older_unchecked": "BORN AS A KEY (R-304, 2026-10-08) -- a NEW sentence of the recovery screen for the agent's 424 (earlier sealed packages not all checked), never a Go literal; pinned by TestR304_OlderUnchecked_IsNotAWrongCode.",