fix(project): race-safe batch scene preview import and close

Serialize updateProject and preview finalize, drain before pack/close, buffer zip entries, and abort finalize cleanly when leaving the project to avoid ENOENT on multi-image drops.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/main/project/zipStore.legacyContract.test.ts

@@ -50,6 +50,17 @@ void test('zipStore: pack and open operations are serialized', () => {
   assert.match(src, /enqueueProjectSwitch/);
 });
 
+void test('zipStore: project updates and preview finalize are serialized', () => {
+  const src = fs.readFileSync(path.join(here, 'zipStore.ts'), 'utf8');
+  assert.match(src, /private projectUpdateChain: Promise<unknown>/);
+  assert.match(src, /private previewFinalizeChain: Promise<unknown>/);
+  assert.match(src, /enqueueProjectUpdate/);
+  assert.match(src, /enqueuePreviewFinalize/);
+  assert.match(src, /finalizeScenePreviewImportInner/);
+  assert.match(src, /drainProjectMutations/);
+  assert.match(src, /addBuffer/);
+});
+
 void test('zipStore: closeOpenProject is serialized with open on projectSwitchChain', () => {
   const src = fs.readFileSync(path.join(here, 'zipStore.ts'), 'utf8');
   assert.match(src, /async closeOpenProject\(\): Promise<void> \{[\s\S]*enqueueProjectSwitch/);