test(app): stabilize archive descriptor assertions

The test rebuilt expected provider rows with fresh timestamps, so its result depended on both fixture calls landing in the same millisecond. Assert the preserved descriptor identities instead, matching the behavior under test without clock dependence.

packages/app/src/subagents/archive-finished.test.ts

@@ -400,9 +400,11 @@ describe("createArchiveFinishedSubagents", () => {
   });
 
   it("dismisses finished provider rows locally without removing their descriptors", async () => {
+    const finishedDescriptor = provider("finished");
+    const runningDescriptor = provider("running", "running");
     const descriptors = new Map([
-      ["finished", provider("finished")],
-      ["running", provider("running", "running")],
+      ["finished", finishedDescriptor],
+      ["running", runningDescriptor],
     ]);
     const dismissed: string[][] = [];
     const archive = createArchiveFinishedSubagents([...descriptors.values()], {
@@ -420,7 +422,7 @@ describe("createArchiveFinishedSubagents", () => {
     });
 
     expect(dismissed).toEqual([["finished"]]);
-    expect(descriptors.get("finished")).toEqual(provider("finished"));
-    expect(descriptors.get("running")).toEqual(provider("running", "running"));
+    expect(descriptors.get("finished")).toBe(finishedDescriptor);
+    expect(descriptors.get("running")).toBe(runningDescriptor);
   });
 });