Fix #1117 persistence stage race slice

[ganesh47]

Refs #1117

Summary

• align Lab concept progress default profile with KidProfileStore.defaultProfileId
• make CardReviewScheduler() use a live clock while preserving explicit fixed-time initializers for tests
• cancel/gate multiple-choice delayed completion tasks across retry/navigation attempt changes
• persist Rectangle Factory solved target count, including the current target before advancing and the final target

Validation

• git diff --check

Remaining #1117 Notes

• The broader persistence save/fetch failure finding remains open. This PR intentionally avoids a risky shared-store API migration; it only fixes the profile-default half of that persistence cluster and the safer independent stage/scoring/scheduler bugs.