F-186 — Implementer evidence

Implemented

Eight quick-product slots rendered in a 4×2 touch grid.
Touch-sized line-discount button; hidden when terminal.settings.lineDiscountsEnabled=false.
Touch payment modal per configured method with “total” / “partial” choice.
Mixed payment allocations remain visible with paid and outstanding totals and can be removed.
Cash tender captures overpayment and previews/records change.
Separate “Confirmar y cerrar ticket” step; disabled until applied amounts equal total.
Receipt modal supports browser print and SMTP email; cashier is only reset after one delivery action completes.
Free-item modal adds non-stock service/product lines by name and positive price.

Terminal config expanded from 4 to 8 quick slots.
Per-terminal discount switch for self-payment terminals.
Payment-method management supports custom active/inactive cash/card/other methods (Bizum, Stripe, Apple Pay labels, etc.; no external processor integration).
Company identity, ticket prefix/next number/padding, header/footer and return-policy settings.

Migration 054_pos_checkout_receipts.js adds transaction-safe receipt settings/sequence, immutable receipt numbers, and nullable stock IDs for CHECK-constrained free lines.
POS sale now reloads catalog prices/names/SKU server-side, locks/decrements stock, rejects disabled discounts/methods, validates exact payment allocation and cash tender, and commits as COMPLETED.
Payment transactions preserve configured method, tender and change in immutable raw data.
Each payment is captured in reporting_payment_lines; this addresses new POS sales not reaching reporting.
Cash session expected balance increases by applied cash, never by tendered cash (change excluded).
Rich receipt builder contains company, time, ticket number, item details, totals, payment allocations, change and return policy.
Receipt access is terminal-scoped for cashier/manager and unrestricted only for admin.
Receipt email uses existing SMTP settings and cannot inject custom content.
POS cashier creation was corrected to use backoffice_users with Argon2 instead of invalid identity rows/SHA-256.

cd project && npm run typecheck — PASS.
cd project && npm test — PASS: 268 unit tests; DB tests skipped without env.
TEST_DATABASE_URL=... npx vitest run --no-file-parallelism — PASS: 78 files / 350 tests, including all real-PostgreSQL integration files sequentially.
New payment-allocation.test.ts — PASS: mixed partial allocation, cash change, exact total, disabled method and legacy mapping.
New pos-checkout-receipts.itest.ts — PASS: complete state, stock decrement, free line, mixed payment/change, reporting capture, receipt sequence, cash expected amount and idempotent replay.
Migration fresh up / no-op second up / full down / re-up — PASS.
POS Next.js production build — PASS.
Admin Next.js production build — PASS (pre-existing dynamic upload tracing warnings only).
./scripts/verify.sh — PASS.
git diff --check — PASS.
Targeted ESLint and Prettier for all changed backend/admin/POS files — PASS.

Root npm run lint remains red on 9 unrelated pre-existing errors in generate-thumbnails.mjs, log-broadcaster.ts, old store-repository.test.ts, and reporting files. Changed files pass targeted ESLint/Prettier.
Boundary violations were reduced from 8 to 1 by adding the POS public index and removing old deep imports. The remaining violation is pre-existing security.routes.ts -> infrastructure/logging/log-broadcaster.ts and is outside F-186.

F-187 cashier deletion/deactivation.
F-188 pending-payment orders (paid POS orders are already COMPLETED here).
F-189 negative quantity returns and return tickets.
F-190 full reporting update/refresh audit (new POS payment lines are captured here).
F-191 terminal and daily close reconciliation.
F-192 simplified storefront VAT label.
F-193 storefront expiry/weight and shipping-weight calculation.