fix: add getList with records wrapper + correct options format from browser capture

internal/provider/rainyun/listdata.go

@@ -0,0 +1,21 @@
+package rainyun
+
+// listOptions returns the standard pagination query for Rainyun list endpoints.
+// Format verified via browser DevTools capture of the Rainyun web console:
+//
+//	https://api.v2.rainyun.com/product/rcs/?options={url-encoded JSON}
+//
+// The decoded JSON is: {"columnFilters":{},"sort":[],"page":1,"perPage":20}
+func listOptions() map[string]string {
+	return map[string]string{
+		"options": `{"columnFilters":{},"sort":[],"page":1,"perPage":50}`,
+	}
+}
+
+// listResponse is the JSON envelope returned by Rainyun list endpoints.
+// The API wraps data in {"code":0,"data":{"records":[...],"totalRecords":N}}.
+// Our client extracts apiResp.Data ({"records":[...]}), then we unmarshal into this.
+type listResponse struct {
+	Records      []any `json:"records"`
+	TotalRecords int   `json:"totalRecords"`
+}