Make AsyncReadyLayerSpec deterministic via TestClock

[EtaCassiopeia]

Summary

AsyncReadyLayerSpec was racing wall-clock timing. The test under `@@ TestAspect.withLiveClock` asserted that providerStatus starts as NotReady then transitions to Ready after a 50ms async delay. On slow CI runners, layer construction itself could take longer than 50ms, causing the first providerStatus read to already see Ready and the assertion to fail. Previously hit in #116's CI run (#25769211402).

Fix

Removed withLiveClock and replaced ZIO.sleep with TestClock.adjust. The forked transition fiber inside asyncReadyLayer uses ZIO.sleep(initDelay), which under TestClock suspends indefinitely until the clock is explicitly advanced. This eliminates the race:

1. Layer constructs. Transition fiber forks and suspends on TestClock.sleep(50.millis).
2. Test reads status → guaranteed NotReady.
3. Test calls TestClock.adjust(60.millis) → fiber's sleep elapses, fiber flips status.
4. Test polls via repeatUntil(_ == Ready) to await the flip (bounded by a 5s live-clock timeout for safety).

Side benefit: the suite now runs in ~160ms instead of ~1.5s (no live-clock sleeps).

Files

• testkit/src/test/scala/zio/openfeature/testkit/AsyncReadyLayerSpec.scala