feat: add Graph Automaton Simulator - cellular automata on graph topologies

Interactive tool for running cellular automata on arbitrary graphs:
- 8 preset topologies (grid, ring, star, K5, Petersen, binary tree, barbell, random)
- 7 built-in rules (Majority, Game of Life, Voter, Anti-Voter, Threshold, Parity, Fredkin)
- Custom rule editor with JavaScript expressions
- 2-6 discrete states with color coding
- Autonomous insights: steady state detection, period-2 oscillation detection,
  state extinction alerts, fragmentation analysis, entropy monitoring, dominance tracking
- State history timeline chart showing population dynamics
- JSON and PNG export
- Full graph editor (add/remove nodes/edges, drag, right-click delete)

Author: sauravbhattacharya001