music: 新建 music app，替换 piano-sheet

听歌 + 练琴曲目管理：
- 数据：piece (title/artist/category/lyrics/play_count/notes) + attachments (audio/video/pdf/image; image 带 role=chord/numbered/staff)
- 后端 axum + sqlite，附件流式落 PVC，ServeFile 支持 Range（视频拖动）
- 前端 guitar 风格 player：左 sidebar + tabs(歌词/吉他谱/简谱/五线谱/PDF/视频)，LRC 同步、快捷键、笔记自动保存
- ns cube-music + music.famzheng.me + bodylimit 5GiB
- scripts/import_guitar.py 用于把 oci /data/guitar/ 旧曲库导入

Cargo.lock

@@ -441,6 +441,21 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "music"
+version = "0.1.0"
+dependencies = [
+ "axum",
+ "cube-core",
+ "rusqlite",
+ "serde",
+ "serde_json",
+ "tokio",
+ "tower",
+ "tower-http",
+ "tracing",
+]
+
 [[package]]
 name = "nu-ansi-term"
 version = "0.50.3"
@@ -485,20 +500,6 @@ version = "2.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9b4f627cb1b25917193a259e49bdad08f671f8d9708acfd5fe0a8c1455d87220"
 
-[[package]]
-name = "piano-sheet"
-version = "0.1.0"
-dependencies = [
- "axum",
- "cube-core",
- "rusqlite",
- "serde",
- "serde_json",
- "tokio",
- "tower-http",
- "tracing",
-]
-
 [[package]]
 name = "pin-project-lite"
 version = "0.2.17"