The library screen's only chrome is now a 40px strip drawn in place of the
native title bar: My Library / Shared / Community tabs on the left; search,
sort, New, and the account on the right. The hover rail, the 70px app bar,
and the never-mounted folder sidebar are gone.

"This Computer" is no longer a destination. My Library shows the local and
cloud stores together at the root, deduplicated by id; local strategies
carry an "On this device" badge while the cloud is reachable. Opening a
folder makes its store active, so every existing per-store path (create,
move, edit, delete) keeps working unchanged. The breadcrumb moved into the
content area and only appears inside a folder.

Window chrome: window_manager hides the native title bar on desktop. macOS
keeps its traffic lights, re-centered on the strip by MainFlutterWindow;
Windows and Linux get app-drawn caption buttons. The editor's top row and
skeleton double as the drag handle.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>