Extend (not replace) home-manager's default sway keybindings via
lib.mkOptionDefault, with lib.mkForce on the custom overrides that
conflict with defaults. Add Mod+F1 cheatsheet binding (fuzzel-filterable).
Move fuzzel's border-radius/border-width out of [main] into a proper
[border] section with the expected short names.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
