Catches the class of DI-graph bugs that motivated both this hotfix and hotfix #23: a module missing an imports/exports entry that type-checks fine, passes unit tests (which `new` providers manually), and only surfaces at real NestJS DI boot time - i.e. production. Test calls `Test.createTestingModule({ imports: [AppModule] }).compile()` which resolves the full provider graph. Does NOT call `.init()` so lifecycle hooks + the real Prisma connection don't fire (fast, DB-independent, ~3 seconds). Verified the test catches both the original ClockService bug (PR #23) and this re-export bug by reverting each fix and re-running.