…duction data

- index.md: Replace fabricated model table with actual 10 models from production
- getting-started.md: Fix model names (deepseek-v3.2 not deepseek-v3) and prices
- api-reference.md: Fix model examples, use generic placeholders for embedding/image
- api-reference.md: Add concrete SDK config for LangChain and LlamaIndex

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

…y ppray"

Add custom _layouts/default.html that replaces the default Cayman theme footer
(which auto-generates "repo is maintained by owner" from GitHub repo info) with
a custom OpenRouterA copyright notice.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

- Add NowPayments (USDT/crypto) as a new top-up payment method
- Backend: webhook handler with HMAC-SHA512 signature verification,
  order creation via NowPayments API, and recharge flow with DB locks
- Frontend: payment settings tab, QR code modal with blockchain
  network auto-detection, and status polling for completion
- Add poll endpoint /api/user/topup/status for real-time status checks
- Fix duplicate NowPaymentsEnabled handling in option map
- Fix anti-pattern errors.New(fmt.Sprintf(...)) -> fmt.Errorf(...)
- Add unit tests for signature verification and pay money calculation
- Add .playwright-mcp/ to .gitignore

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

- fix float precision loss in signature verification using json.RawMessage
- remove unused fields from NowPaymentsWebhookData (PaymentId, PurchaseId, CreatedAt, UpdatedAt)
- add PayAddress to TopUp model and save it when creating order
- add pay_address to success log for audit
- add precision regression tests (large integer, float precision)