The zauc-mocks-hook variant previously asserted that session.created synchronously
ran the startup checks. After auto-update-checker was refactored to defer work to
the first session.idle via scheduleDeferredIdleCheck (5s timer), those assertions
never fired.
Mirror the mock+capture pattern from hook.test.ts so the test drives the deferred
callback synchronously, preserving the original invariants (hasChecked guard,
localDev toast, sisyphus wording) without waiting on real timers.
Sisyphus
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