🐛 fix(thirdparty): preserve manifest during snapshot update

tests/test_thirdparty_skills_pipeline.py

@@ -80,6 +80,18 @@ class ThirdpartySkillsPipelineTests(unittest.TestCase):
         self.assertTrue((UI_UX_PRO_MAX_DIR / "data").is_dir())
         self.assertTrue((UI_UX_PRO_MAX_DIR / "scripts").is_dir())
 
+    def test_update_script_materializes_manifest_before_target_checkout(self):
+        text = UPDATE_SCRIPT.read_text(encoding="utf-8")
+        self.assertIn('manifest_copy="$tmp_dir/thirdparty_skills.json"', text)
+        self.assertIn('cp "$MANIFEST_PATH" "$manifest_copy"', text)
+        self.assertIn('MANIFEST_PATH="$manifest_copy"', text)
+        self.assertIn('if ! emit_sources_tsv > "$sources_file"; then', text)
+        self.assertNotIn("done < <(emit_sources_tsv)", text)
+        self.assertLess(
+            text.index('cp "$MANIFEST_PATH" "$manifest_copy"'),
+            text.index('git checkout -B "$TARGET_BRANCH" "origin/$TARGET_BRANCH"'),
+        )
+
 
 if __name__ == "__main__":
     unittest.main()