Signed in, a local strategy or folder can move to the cloud: "Move to
cloud" in its menu, or a drop on a cloud folder. A move builds the cloud
copy under new ids and keeps it out of every library list (the server's
unfinishedMove flag): the strategy with its pages, its items and lineups
in batches bound to the account, then its pictures through the upload
queue under fresh picture ids. The copy is read back and checked, then
finished, and only then is the local original deleted. When anything
fails, the copy is abandoned, the original stays, and the user is told.
A record of each move outlives a quit, so the next sign-in abandons
what a move left unfinished; the server deletes only unfinished copies.

While a strategy moves, neither it nor its cloud copy can be opened: the
library dims it and says "Moving to cloud", and the editor's load paths,
mouse history and the quick switcher refuse it. Local folders now say
they are only on this computer, as local strategies do.

The unused CloudMigrationNotifier, which nothing called, is replaced.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>