Mobile Responsiveness Improvements

# Mobile Responsiveness Improvements

**Priority:** High

## Description
The current interface needs significant improvements for mobile users. Touch interactions are not optimized and the layout breaks on smaller screens.

## Current Issues
- Buttons are too small for touch interaction
- Node creation is difficult on touch devices
- Canvas doesn't resize properly on mobile
- Edge creation is unreliable on touch screens

## Required Improvements
1. Touch Interface:
- [ ] Larger touch targets for all interactive elements
- [ ] Touch-friendly node creation mechanism
- [ ] Improved edge creation for touch devices
- [ ] Pinch-to-zoom functionality

2. Responsive Layout:
- [ ] Dynamic canvas sizing
- [ ] Collapsible controls panel
- [ ] Mobile-first button arrangement
- [ ] Responsive typography

## Technical Considerations
- Minimum touch target size: 44x44px
- Use native touch events instead of mouse events
- Implement proper viewport meta tags
- Consider progressive enhancement approach

## Acceptance Criteria
- All functions should work on mobile devices
- Interface elements should be easily tappable
- No horizontal scrolling on mobile
- Smooth performance on mid-range devices