fix(appearance): stage a cursor theme, apply on confirmHEADmaster

Clicking a cursor card called applyCursor straight away, so the pointer,
gsettings, environment.lua and both GTK settings files all changed on a
single click with nothing to confirm. The wallpaper tab already stages a
pick and commits it from an Apply button; the cursor grid now does the
same, with a Reset beside it.

The hover preview is unchanged: it still switches the real cursor and
reverts on unhover, which is what makes staging readable, you see the
theme before committing to it. That preview is also why Apply clears
liveCursorCursor before calling applyCursor. Moving the mouse off the
card to reach the button fires the unhover revert, which would otherwise
set the old theme back over the one just applied.

A staged card takes the solid accent border and the current one drops to
a half-alpha border, so both stay visible at once.

Icon themes and cursor size still apply on click. Neither has a hover
preview to confirm against.

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

0 files changed, 0 insertions, 0 deletions