fix(migrations): dropping the demo also takes its reset job's interval-change audit rows

0098 deleted the reset job's run rows but not the scheduler_interval rows that changing its interval
wrote; with the job's label gone they rendered as a raw id. The delete now takes every job-targeted
row for it, and a test seeds both kinds below 0098 and upgrades (red on the old filter). The test
has its own file so the removed-features guard can name it.

frontend/src/lib/removedFeatures.contract.test.ts

@@ -9,7 +9,8 @@ import { describe, expect, it } from "vitest";
 //
 // Not scanned: the Alembic migrations (0014 added the account and 0098 removed it, and both stay true
 // as history) and the release notes, which record what shipped when. `audit_metrics.py` counts the
-// footprint by this same word, so it names it on purpose.
+// footprint by this same word, and test_migration_0098.py tests the removal itself, so both name it
+// on purpose.
 
 const REPO = new URL("../../../", import.meta.url);
 const ROOTS = ["backend/app", "backend/tests", "frontend/src", "frontend/e2e", "scripts"];
@@ -18,6 +19,7 @@ const EXTENSIONS = /\.(py|ts|tsx|js|mjs|json|css|md|sh)$/;
 const ALLOWED = new Set([
   "frontend/src/lib/removedFeatures.contract.test.ts",
   "scripts/audit_metrics.py",
+  "backend/tests/test_migration_0098.py",
 ]);
 // "demo" as a word or an identifier part (`is_demo`, `DemoBanner`, `tryDemo`) — not "demote" (a role
 // change) and not "Demokratikus" (a country's Hungarian name in the vocab).