Adds comprehensive touch event handling system for mobile devices,
addressing issue ikuaitu#556.

Changes:
✅ Created TouchEventHandler class (350+ lines)
✅ Created useTouchEvents Vue composable
✅ Touch gesture support
✅ Multi-touch support
✅ Device detection utilities

Touch Gestures Supported:
- Tap (single touch)
- Double tap (quick succession)
- Long press (500ms hold)
- Swipe (left, right, up, down)
- Pinch zoom (two-finger scale)
- Rotate (two-finger rotation)

Features:
- Configurable thresholds
- Velocity-based swipe detection
- Center point calculation for pinch/rotate
- Touch point tracking
- Event callbacks system
- Passive event listeners for performance
- Touch action prevention

API:
- TouchEventHandler class for direct use
- useTouchEvents() composable for Vue 3
- isTouchDevice() helper
- preventDefaultTouch() helper

Usage Example:

Benefits:
- Native touch support
- Better mobile UX
- Gesture recognition
- Multi-touch capable
- Performance optimized
- Easy integration

This is part 3 of 4 for mobile integration.

Part of ikuaitu#556