Track voucher_type_at_purchase on gift card creation. Apply VAT at gift card purchase (SPV), at redemption (MPV). Use transaction-aware GetCardByIDQuerier for till saved card lookups. Apply VAT to all booking payments (split records, terminal, tip, checkout). Add TotalVATAmount and TotalNetAmount to PaymentSummary responses.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Replace direct *pgxpool.Pool usage with PoolProxy wrapper across the entire backend:
- db.DB renamed to db.Conn (*pgxpool.Pool -> *PoolProxy)
- JWT functions now accept context.Context instead of using context.Background()
- Handler DB calls route through PoolProxy for per-test transaction support
- Fixture/helper/testdb functions accept Querier interface for decoupling
- Query ordering fixed in bookings handlers: COUNT after data query to avoid pgx conn busy
- Time truncation fixed: time.Date instead of Truncate(24*time.Hour) for week start calc
- testmain_test.go files updated with SeedBaseline and NewPoolProxy
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
- Added generic formatAndPreserveCursor() helper on frontend to track
and restore selection caret position during dynamic input sanitization
- Applied to all card inputs, gift card code inputs, and expiry inputs
- Added Luhn validation (isValidLuhn) for saved cards and gift cards
- Rebuilt payments test DB and got 100% green tests