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.

.forgejo/workflows/mirror.yml

@@ -0,0 +1,21 @@
+name: Mirror to GitHub
+
+on:
+  push:
+    branches: ['**']
+    tags: ['**']
+
+jobs:
+  mirror:
+    runs-on: [self-hosted, hestia]
+    steps:
+      - name: Mirror to GitHub
+        run: |
+          set -euo pipefail
+          git clone --mirror "https://git.breadway.dev/${GITHUB_REPOSITORY}.git" repo.git
+          cd repo.git
+          # Mirror only branches and tags (not refs/pull/*, which GitHub rejects);
+          # --prune deletes GitHub refs that no longer exist on Forgejo.
+          git push --prune \
+            "https://x-access-token:${{ secrets.MIRROR_TOKEN }}@github.com/Breadway/bos-settings.git" \
+            '+refs/heads/*:refs/heads/*' '+refs/tags/*:refs/tags/*'