🐛 fix(sync): keep agents block blank lines

tests/cli/test_playbook_cli.py

@@ -101,6 +101,30 @@ langs = ["tsl"]
             self.assertEqual(result.returncode, 0)
             self.assertTrue(agents_index.is_file())
 
+    def test_sync_standards_agents_block_has_blank_lines(self):
+        with tempfile.TemporaryDirectory() as tmp_dir:
+            config_body = f"""
+[playbook]
+project_root = "{tmp_dir}"
+
+[sync_standards]
+langs = ["tsl"]
+"""
+            config_path = Path(tmp_dir) / "playbook.toml"
+            config_path.write_text(config_body, encoding="utf-8")
+
+            result = run_cli("-config", str(config_path))
+            self.assertEqual(result.returncode, 0)
+
+            agents_md = Path(tmp_dir) / "AGENTS.md"
+            lines = agents_md.read_text(encoding="utf-8").splitlines()
+            start_idx = lines.index("<!-- playbook:agents:start -->")
+            end_idx = lines.index("<!-- playbook:agents:end -->")
+            block = lines[start_idx : end_idx + 1]
+            self.assertEqual(block[1], "")
+            bullet_idx = next(i for i, line in enumerate(block) if line.startswith("- "))
+            self.assertEqual(block[bullet_idx - 1], "")
+
     def test_install_skills(self):
         with tempfile.TemporaryDirectory() as tmp_dir:
             target = Path(tmp_dir) / "codex"