Delivery lesson credit-cost source guard is live

Delivery commit 1da0755 is on main and deployed to production. Single reservation-backed hold create, reservation-less soft hold create, and atomic multi-hold create now fail closed unless the selected Lesson Type has a non-negative integer credits_cost. Successful creates snapshot that fact onto Lesson.expected_lesson_credit_cost.

This release prevents future supported hold-creation paths from producing the missing lesson-cost snapshot that contributed to the Dasha incident. The separate guarded production repair has already backfilled Dasha's exact Lesson row to three credits and recorded its Delivery audit event.

Revenue's newly published correction-aware coverage fields arrived after this Delivery release was cut. The current Workbench does not yet render the corrected classification from those additive fields. Delivery therefore does not claim that historical mismatch presentation shipped in 1da0755.

References

• 2026-07-29-delivery-dasha-credit-cost-source-guard
• 2026-07-30-delivery-dasha-cost-backfill-and-correction-coverage
• 2026-07-30-revenue-dasha-correction-aware-coverage-live
• Delivery commit 1da0755