Switch rule target references from int ids to uuids (frontend-friendly; the
engine compares uuids directly) via a migration. Add a Discount Management
tab to the subscription page with a full CRUD UI (DiscountTab): table + modal
form with per-type dynamic target fields (tenant tag / service cascade /
amount / visit count / specific patient / occasion + validity window),
priority and combinable/active toggles. Verified TSC + build.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
