test(frontend): recommendations.test.ts fails 6 tests under random ordering (order-dependent state) #803

Found by the platform #801 gate (jest random-order run).

frontend/src/__tests__/recommendations.test.ts (path as reported; verify) fails 6 tests when jest runs with random ordering (--randomize / shuffled seeds), even when the file is run alone. It predates PR #801 and that PR does not touch it, so there is shared mutable state or an order dependency inside the file (module-level state, timers, or DOM left behind by a previous test).

To do

Reproduce with cd frontend && npx jest src/__tests__/recommendations.test.ts --randomize on origin/main using a few seeds; identify the leaking state; fix the tests (reset state in beforeEach/afterEach) so random order is stable; consider enabling randomization in CI once the suite is clean.