v0.2.0: Device menu — sync a playlist to the Rabbit R1

New Device menu (left of Track) with "Sync Playlist to Rabbit", enabled
only when a playlist is showing and the Rabbit is plugged in. The Rabbit
mounts over MTP/gvfs (not mass storage), so device_sync.py drives it
with plain file I/O honoring the MTP caveats: no copystat, diff by
name+size. One-way mirror into Music/<Playlist>/ on the device — stale
files deleted (that folder only), Auxio-importable .m3u carries the
order, free space checked up front with a needed-vs-available alert, and
a right-justified status-bar progress bar tracks the chunked copies.
Verified live against the real Rabbit end to end.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CLAUDE.md

@@ -97,6 +97,14 @@ persistence) → GUI (Qt widgets that read the manager and connect to its signal
   so the desktop's media keys / now-playing popup control playback. Spacebar and
   arrow keys are handled locally via `MainWindow.eventFilter`.
 
+- **`lintunes/device_sync.py`** — one-way playlist sync to the Rabbit R1 (Device
+  menu). The Rabbit mounts via **MTP/gvfs** (a FUSE path under
+  `/run/user/<uid>/gvfs`), not mass storage — so plain file I/O, but never
+  copystat and never trust mtimes (diff by name+size). Sync owns exactly
+  `Music/<Playlist Name>/` on the device (creates/overwrites/deletes there,
+  plus an Auxio-importable `.m3u`); it never deletes outside that folder and
+  only ever *reads* local library files.
+
 ## Conventions & gotchas
 
 - **Tests are organized as `tests/test_roundN.py`** — each development round adds