Fix cross-DB queries: move page_configs to cart, fix OAuth code_hash lookup

page_configs table lives in db_cart but blog was querying it directly,
causing UndefinedTableError. Move all PageConfig read/write endpoints to
cart service and have blog proxy via fetch_data/call_action.

Also fix OAuth callback to use code_hash lookup (codes are now stored
hashed) and pass grant_token in redirect URL to prevent auth loops.

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

blog/bp/actions/routes.py

@@ -31,51 +31,13 @@ def register() -> Blueprint:
         result = await handler()
         return jsonify(result or {"ok": True})
 
-    # --- update-page-config ---
+    # --- update-page-config (proxy to cart, where page_configs table lives) ---
     async def _update_page_config():
-        """Create or update a PageConfig (used by events payment admin)."""
-        from shared.models.page_config import PageConfig
-        from sqlalchemy import select
+        """Create or update a PageConfig — proxies to cart service."""
+        from shared.infrastructure.actions import call_action
 
         data = await request.get_json(force=True)
-        container_type = data.get("container_type", "page")
-        container_id = data.get("container_id")
-        if container_id is None:
-            return {"error": "container_id required"}, 400
-
-        pc = (await g.s.execute(
-            select(PageConfig).where(
-                PageConfig.container_type == container_type,
-                PageConfig.container_id == container_id,
-            )
-        )).scalar_one_or_none()
-
-        if pc is None:
-            pc = PageConfig(
-                container_type=container_type,
-                container_id=container_id,
-                features=data.get("features", {}),
-            )
-            g.s.add(pc)
-            await g.s.flush()
-
-        if "sumup_merchant_code" in data:
-            pc.sumup_merchant_code = data["sumup_merchant_code"] or None
-        if "sumup_checkout_prefix" in data:
-            pc.sumup_checkout_prefix = data["sumup_checkout_prefix"] or None
-        if "sumup_api_key" in data:
-            pc.sumup_api_key = data["sumup_api_key"] or None
-
-        await g.s.flush()
-
-        return {
-            "id": pc.id,
-            "container_type": pc.container_type,
-            "container_id": pc.container_id,
-            "sumup_merchant_code": pc.sumup_merchant_code,
-            "sumup_checkout_prefix": pc.sumup_checkout_prefix,
-            "sumup_configured": bool(pc.sumup_api_key),
-        }
+        return await call_action("cart", "update-page-config", payload=data)
 
     _handlers["update-page-config"] = _update_page_config