Add page_config support to SumUp create_checkout

Accept optional page_config parameter to use per-page
SumUp merchant code and API key instead of global config.

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

browser/app/payments/sumup.py

@@ -42,8 +42,16 @@ async def create_checkout(
     redirect_url: str,
     webhook_url: str | None = None,
     description: str | None = None,
+    page_config: Any | None = None,
 ) -> Dict[str, Any]:
     settings = _sumup_settings()
+
+    # Per-page SumUp credentials override globals
+    if page_config and getattr(page_config, "sumup_api_key", None):
+        settings["api_key"] = page_config.sumup_api_key
+    if page_config and getattr(page_config, "sumup_merchant_code", None):
+        settings["merchant_code"] = page_config.sumup_merchant_code
+
     # Use stored reference if present, otherwise build it
     checkout_reference = order.sumup_reference or f"{settings['checkout_reference_prefix']}{order.id}"