Add gesture support to Sway and fix double waybar issue
Changes:
- Added libinput-gestures config for 3-finger swipe gestures
- Added libinput-gestures to Sway autostart
- Added libinput-gestures to packages.txt
- Fixed double waybar issue by removing redundant bar block
Gestures configured:
- 3-finger swipe left/right: switch workspaces
- 3-finger swipe up: reserved for workspace overview (if available)