Astra's second review found the copy inferring that the new page existed
from the queue: an op leaves the queue when it lands, but also when it
is discarded, replaced, or not yet written, so copies could go to a page
that wasn't there. "+" on a cloud strategy now adds the page with a
direct server call (pages:add), retrying once after a teammate's change,
and copies onto it only once that call succeeds; offline, no page is
added and a toast says so. enqueueOffCanvas checks, as it writes, that
the strategy the copy belongs to is still the active one. The page read
before turning to the new page is bound by the same three seconds, and a
failed turn is logged rather than thrown.

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