Extract bos-settings into its own repo; add Appearance/Startup Apps/Display editors

Split out of the bos repo so a bos-settings release no longer requires a
BOS ISO release (and vice versa) — CI here publishes straight to the
[breadway] pacman repo on tag push, independent of bos's own release cadence.

Also adds real GUI editors for the Hyprland JSON config surfaces bos gained
recently (hypr/settings.json, hypr/monitors.json, hypr/autostart.json):
- Appearance panel: gaps, borders (with a real color picker), blur, shadow,
  tiling layout, and basic input settings.
- Display panel: a monitor-rule list editor alongside the existing live
  connected-monitor readout.
- Startup Apps panel: toggle/edit/add/remove the extra autostart commands.
- --page argv support for deep-linking (breadhelp's guides can now open
  bos-settings straight to a specific page).
- Fixed a stale "View keybinds cheat sheet" button pointing at a file
  deleted when breadhelp replaced bos-keybinds/bos-welcome.

src/ui/sidebar.rs

@@ -37,11 +37,13 @@ pub const SYSTEM_ITEMS: &[SidebarItem] = &[
     item("sound", "Sound", "audio-volume-high-symbolic"),
     item("power", "Power", "battery-good-symbolic"),
     item("datetime", "Date & Time", "preferences-system-time-symbolic"),
-    item_sub("hyprland", "Display", "hyprland.lua", "video-display-symbolic"),
+    item_sub("hyprland", "Display", "monitors.json", "video-display-symbolic"),
+    item_sub("autostart", "Startup Apps", "autostart.json", "system-run-symbolic"),
     item("users", "Users", "system-users-symbolic"),
 ];
 
 pub const PERSONALIZATION_ITEMS: &[SidebarItem] = &[
+    item_sub("appearance", "Appearance", "settings.json", "applications-graphics-symbolic"),
     item_sub("breadpaper", "Wallpaper", "breadpaper", "preferences-desktop-wallpaper-symbolic"),
     item_sub("breadbar", "Bar", "breadbar", "view-grid-symbolic"),
     item_sub("breadbox", "Launcher", "breadbox", "view-app-grid-symbolic"),