Add page_config support to get_checkout for per-page SumUp credentials

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

browser/app/payments/sumup.py

@@ -115,9 +115,13 @@ async def create_checkout(
     return data
 
 
-async def get_checkout(checkout_id: str) -> Dict[str, Any]:
+async def get_checkout(checkout_id: str, page_config: Any | None = None) -> Dict[str, Any]:
     """Fetch checkout status/details from SumUp."""
     settings = _sumup_settings()
+
+    if page_config and getattr(page_config, "sumup_api_key", None):
+        settings["api_key"] = page_config.sumup_api_key
+
     headers = {
         "Authorization": f"Bearer {settings['api_key']}",
         "Content-Type": "application/json",