feat(packages): add standalone auth and payment

README.md

@@ -2,8 +2,30 @@
 
 Shared client packages consumed by `marketplaces` and other projects.
 
-- `packages/auth` — `@marketplaces/auth`. Real implementation. Two independent mechanisms: `telegram/` (live QR/session auth, customer + admin) and `ed25519/` (challenge/response admin auth, backend not shipped yet).
-- `packages/payment` — `@marketplaces/payment`. Scaffold only, no implementation yet.
+- `packages/auth` — `@marketplaces/auth`. Standalone Angular UI + gateway for QR, credentials and Yandex auth.
+- `packages/payment` — `@marketplaces/payment`. Standalone Angular UI + gateway for QR, card, SBP and Yandex Pay.
+
+The packages call separate central services. They never derive or call the tenant API. Each request automatically includes the page hostname as `X-Marketplace-Domain`; central Auth/Payment APIs resolve that domain to the project.
+
+```ts
+bootstrapApplication(AppComponent, {
+  providers: [
+    provideHttpClient(),
+    provideMarketplacesAuth({ apiUrl: 'https://auth.example.net' }),
+    provideMarketplacesPayment({ apiUrl: 'https://payments.example.net' }),
+  ],
+});
+```
+
+```html
+<mp-auth qr credentials yandex mode="admin"
+  (authenticated)="onLogin($event)" />
+
+<mp-payment qr card sbp yandexPay [request]="checkout"
+  (completed)="onPaid($event)" />
+```
+
+Import `MarketplacesAuthComponent` / `MarketplacesPaymentComponent` into the consuming standalone component. See `docs/BACKEND-CONTRACT.md` for central API and CORS requirements.
 
 Consumer documentation lives in the `marketplaces` repo: `docs/PACKAGES-USAGE.md`. Rationale: `docs/context/adrs/ADR-0001-extract-auth-and-payment-into-shared-marketplaces-packages.md`.