fix(tests): keep the preview turn-budget test inside its timeout under CPU load

The four-patch turn-budget test drove 2,400 deltas over a ~300 KB base, about
2.4 s of CPU on an idle machine and 11-15 s at load 150, past the 10 s test
timeout. Pacing already runs on fake timers; the flake was CPU time, not wall
clock. Four 30 s patches at a 500 ms tick still stream ~25 MB uncapped against
the 8 MiB budget, so the test still fails when the cap is removed.

Author: waleedlatif1

apps/sim/lib/mothership/request/go/file-preview-adapter.test.ts

@@ -268,11 +268,17 @@ describe('processFilePreviewStreamEvent — preview byte rate', () => {
     expect(completed).toBe(true)
   })
 
+  /**
+   * Each 30 s patch of the ~300 KB file would stream ~6 MB of snapshots on its own,
+   * so four of them exceed the turn budget several times over without its cap. The
+   * 500 ms tick keeps the delta count, and so the test's CPU time, small enough to
+   * stay far inside the test timeout on a loaded machine.
+   */
   it('bounds all preview content in a turn of four long patches, and still completes each', async () => {
     const turn = newTurn()
     let contentBytes = 0
     for (let edit = 0; edit < 4; edit++) {
-      const result = await streamPatch(120_000, 200, { turn, edit })
+      const result = await streamPatch(30_000, 500, { turn, edit })
       expect(result.completed).toBe(true)
       contentBytes += result.contentBytes
     }