test(copilot): declare the ratio-test expansion instead of carrying it

The compression-ratio case built a real 400 MiB string and deflated it
synchronously, costing the parallel test runner memory and CPU for no added
coverage. The guard reads the total the archive declares, so declaring the
expansion exercises the same ratio path with a few-hundred-byte fixture.

Still fails when the guard call is removed, and the file now runs in 286 ms
instead of seconds.

Caught by Greptile review.

Author: waleedlatif1

apps/sim/lib/copilot/vfs/document-style.test.ts

@@ -144,10 +144,15 @@ describe('extractDocumentStyle', () => {
   })
 
   it('never hands JSZip an archive with an implausible compression ratio', async () => {
+    // 400 MiB sits under the 1 GiB absolute cap, so this exercises the ratio
+    // check rather than the size check. Declaring the expansion rather than
+    // carrying it keeps the fixture a few hundred bytes — the guard reads the
+    // declared total, so a real payload would only cost the suite memory.
     const bomb = buildZip([
       {
         name: 'word/theme/theme1.xml',
-        content: 'A'.repeat(400 * 1024 * 1024),
+        content: THEME_XML,
+        declaredUncompressedSize: 400 * 1024 * 1024,
       },
     ])