feat(sequences): multi-lane playback and per-lane manual beats

- Add sequence_playback with beat and time advance, zone targeting fixes
- Per-lane manual beat routing in beat_driver_route (parallel lanes)
- Sequence API, editor JS, fix sequence model filename, tests

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

tests/test_endpoints_pytest.py

@@ -123,7 +123,7 @@ def server(monkeypatch, tmp_path_factory):
     import models.pallet as models_pallet  # noqa: E402
     import models.scene as models_scene  # noqa: E402
     import models.pattern as models_pattern  # noqa: E402
-    import models.squence as models_sequence  # noqa: E402
+    import models.sequence as models_sequence  # noqa: E402
     import models.device as models_device  # noqa: E402
 
     for cls in (
@@ -527,21 +527,24 @@ def test_groups_sequences_scenes_palettes_patterns_endpoints(server):
     assert resp.status_code == 200
 
     # Sequences.
-    unique_seq_group_name = f"pytest-seq-group-{uuid.uuid4().hex[:8]}"
+    unique_seq_name = f"pytest-seq-{uuid.uuid4().hex[:8]}"
     resp = c.post(
         f"{base_url}/sequences",
-        json={"group_name": unique_seq_group_name, "presets": []},
+        json={
+            "name": unique_seq_name,
+            "steps": [{"preset_id": "1", "group_ids": []}],
+        },
     )
     assert resp.status_code == 201
     sequences_list = c.get(f"{base_url}/sequences").json()
-    seq_id = _find_id_by_field(sequences_list, "group_name", unique_seq_group_name)
+    seq_id = _find_id_by_field(sequences_list, "name", unique_seq_name)
 
     resp = c.get(f"{base_url}/sequences/{seq_id}")
     assert resp.status_code == 200
 
-    resp = c.put(f"{base_url}/sequences/{seq_id}", json={"sequence_duration": 1234})
+    resp = c.put(f"{base_url}/sequences/{seq_id}", json={"step_duration_ms": 1234})
     assert resp.status_code == 200
-    assert resp.json()["sequence_duration"] == 1234
+    assert resp.json()["step_duration_ms"] == 1234
 
     resp = c.delete(f"{base_url}/sequences/{seq_id}")
     assert resp.status_code == 200