settings: every page commits from the header

The Mail, Assistant and Ask presets pages got a Save and Discard pair in
the page header; the rest still had their own buttons wherever their
page put them: User's Save at the bottom, Wallpaper's Apply and Reset
beside the mock screens, Icons' Apply and Reset under the cursor cards,
HyprSunset's and HyprIdle's Save + Restart in the page. They now all sit
in the header SaveBar, which takes the page's own verbs (Apply and
Reset, Save + Restart) and a busy state.

HyprSunset and HyprIdle had no notion of an unsaved change, so their
button was always live. They now count as changed when what save()
would write differs from what was read, which enables Save only then,
gives Discard (a reload) something to drop, and marks them in the
sidebar; a window open no longer reloads them over unsaved edits. The
staged cursor moved from IconsTab into the Icons singleton so the
header and the sidebar can see it.

Git and autostart act a row at a time, and a theme applies on click, so
those have no bar.

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

1 files changed, 2 insertions, 1 deletions

diff --git a/desktop/modules/appearance/README.md b/desktop/modules/appearance/README.md
index 51e5f09..b80b564 100644
--- a/desktop/modules/appearance/README.md
+++ b/desktop/modules/appearance/README.md
@@ -65,7 +65,8 @@ waybar-theme-udt's `install.sh` or signals waybar.
 ## Wallpapers
 
 Clicking a thumbnail **stages** it rather than setting it, so both screens can
-be composed before anything changes, and Apply then makes a single
+be composed before anything changes, and Apply, in the page header like
+every settings page's commit, then makes a single
 `wallp --set H=… V=…` call. The mock screens above the list show what the desk
 would look like: the staged pick where there is one, what is currently set
 where there is not, and the hovered thumbnail on the targeted screen while the