feat(keybinds): move window focus to SUPER+arrows

Swap the vim-style SUPER+H/J/K/L focus binds for SUPER+arrow keys
(movefocus l/r/u/d). SUPER+arrows were unbound and there are no vim
move-window binds, so no collision. prettyKeys renders the arrow keysyms
as glyphs so the SUPER+? cheatsheet shows "SUPER + <-" not "SUPER + left".

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

agent/HARDWARE-QUEUE.md

@@ -236,6 +236,9 @@ QA machine), the **T14s** (webcam case).
       unchanged (the bar still reserves its space). Accepted trade-off
       of `layer: bottom`: a floating window dragged over the top strip
       can now overlap the bar — confirm that's the only regression.
+- [ ] **Window focus on arrows** (iteration #61) — after `home-update` +
+      relogin: SUPER+←/→/↑/↓ move focus between tiled windows; SUPER+H/J/K/L
+      no longer move focus; SUPER+? cheatsheet shows the arrow glyphs.
 - [ ] **Audio opens in Amberol** (iteration #60, item 37) — after
       `home-update`: double-click an mp3/flac/ogg (or `xdg-open song.mp3`)
       → it opens in Amberol, not mpv; video files still open in mpv.