Comprehensive README rewrite matching moltbot style

- Centered hero with demo GIF and badges (for-the-badge style)
- Navigation links at top
- Clear feature sections with bullet lists
- Platform tables with checkmarks
- All commands documented with descriptions
- Detailed architecture diagram
- Full configuration examples (env + JSON)
- Safety & security section
- Channel setup guides (Telegram, Discord, Slack)
- Arbitrage detection explanation with examples
- Contributing section
- ~435 lines of comprehensive documentation

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: alsk1992