fix: Resolve unhandled promise rejection in retry.spec.ts

The test "should verify exponential backoff timing" was creating a promise
that rejects but never awaited it, causing an unhandled rejection error.
Changed the test to properly await the promise rejection with expect().rejects.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/api/src/federation/utils/retry.spec.ts

@@ -160,21 +160,25 @@ describe("Retry Utility", () => {
       expect(operation).toHaveBeenCalledTimes(4);
     });
 
-    it("should verify exponential backoff timing", () => {
+    it("should verify exponential backoff timing", async () => {
       const operation = vi.fn().mockRejectedValue({
         code: "ECONNREFUSED",
         message: "Connection refused",
         name: "Error",
       });
 
-      // Just verify the function is called multiple times with retries
-      const promise = withRetry(operation, {
-        maxRetries: 2,
-        initialDelay: 10,
+      // Verify the function attempts multiple retries and eventually throws
+      await expect(
+        withRetry(operation, {
+          maxRetries: 2,
+          initialDelay: 10,
+        })
+      ).rejects.toMatchObject({
+        message: "Connection refused",
       });
 
-      // We don't await this - just verify the retry configuration exists
-      expect(promise).toBeInstanceOf(Promise);
+      // Should be called 3 times (initial + 2 retries)
+      expect(operation).toHaveBeenCalledTimes(3);
     });
   });
 });