Extends commands/paste.rs so that when auto-paste fires we:
1. capture the user's existing clipboard text BEFORE overwriting
it with the transcript (via arboard::Clipboard::get_text — a
non-text clipboard returns None and the restore step is
skipped, which keeps images / files safe),
2. after the paste keystroke lands, sleep 300 ms,
3. restore the snapshot only if the clipboard still holds the
transcript we wrote — respects any Cmd+C the user did in the
300 ms window.
Moves the decision to a pure should_restore(current, transcript)
helper with four unit tests. The existing paste-matrix regression
tests are unchanged.
Matches Handy #921 (workstream-B brief item #3). Coexists with the
Wayland preview-hide dance already in this file, and doesn't run
when the paste keystroke fails (transcript stays on the clipboard
for the user's own paste).
Co-authored-by: jars <jakejars@users.noreply.github.com>
f3a0673eaa