fix(app): update route test expectations for b64_ workspace ID prefix

The opaque-workspace-identifier refactor (e6044264) added a `b64_` prefix
to base64-encoded workspace IDs in route builders. Two app tests still
expected the unprefixed form and failed in CI.

packages/app/src/utils/workspace-navigation.test.ts

@@ -46,7 +46,7 @@ describe("prepareWorkspaceTab", () => {
       target: { kind: "agent", agentId: AGENT_ID },
     });
 
-    expect(route).toBe("/h/server-1/workspace/L3JlcG8vd29ya3RyZWU");
+    expect(route).toBe("/h/server-1/workspace/b64_L3JlcG8vd29ya3RyZWU");
     const key = "server-1:/repo/worktree";
     expect(useWorkspaceLayoutStore.getState().getWorkspaceTabs(key)).toHaveLength(1);
   });