✨ feat: keyboard shortcut setup wizard (0.8.0)

- Add --setup-shortcut flag to configure a desktop keybinding
- Wizard runs automatically on first run after config creation
- Supports Hyprland (bindings.conf + hyprctl conflict check),
  GNOME (gsettings) and KDE (kglobalshortcutsrc)
- Hyprland: prefers omarchy-launch-tui, falls back to xdg-terminal-exec
- Conflict detection with fallback combo suggestions
- Add tmuxido.desktop and install icon + .desktop in install.sh
- 157 tests passing

tmuxido.desktop

@@ -0,0 +1,10 @@
+[Desktop Entry]
+Name=Tmuxido
+Comment=Quickly find and open projects in tmux
+Exec=tmuxido
+Icon=tmuxido
+Type=Application
+Categories=Development;Utility;
+Terminal=true
+Keywords=tmux;project;fzf;dev;
+StartupWMClass=tmuxido