test: cover zone content kind lock and sequence groups

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

tests/test_zone_content_kind.py

@@ -0,0 +1,27 @@
+"""Zone content_kind is fixed after create."""
+
+import json
+import os
+import sys
+import tempfile
+from pathlib import Path
+
+PROJECT_ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(PROJECT_ROOT / "src"))
+
+from models.zone import Zone  # noqa: E402
+
+
+def test_update_cannot_change_content_kind():
+    with tempfile.TemporaryDirectory() as tmp:
+        path = os.path.join(tmp, "zone.json")
+        with open(path, "w", encoding="utf-8") as f:
+            json.dump({}, f)
+        z = Zone()
+        z.file = path
+        z.clear()
+        zid = z.create("preset zone", group_ids=[], content_kind="presets")
+        z.update(zid, {"content_kind": "sequences", "name": "preset zone"})
+        doc = z.read(zid)
+        assert doc["content_kind"] == "presets"
+        assert doc.get("sequence_ids") == []