refactor(core): extract shared dedup helpers

src/plugin-sdk/request-url.ts

@@ -0,0 +1,12 @@
+export function resolveRequestUrl(input: RequestInfo | URL): string {
+  if (typeof input === "string") {
+    return input;
+  }
+  if (input instanceof URL) {
+    return input.toString();
+  }
+  if (typeof input === "object" && input && "url" in input && typeof input.url === "string") {
+    return input.url;
+  }
+  return "";
+}