BREAKING: Full ground-up rewrite. Nothing from the old codebase survives.

Architecture:
- Immutable domain types with Decimal arithmetic (no floats for money)
- Exchange adapter pattern (ABC) with Binance implementation
- Graph-based triangle discovery (auto-adapts to new listings)
- Order-book-aware profit evaluation with 3-leg fee compounding
- Sequential tri-leg execution with best-effort rollback
- Risk manager with circuit breakers and drawdown guards
- Async event loop (asyncio, not threads)
- Structured JSON logging via structlog
- Pydantic-validated YAML config (fail-fast on invalid config)

Testing & CI:
- 24 unit tests covering discovery, evaluation, risk, and types
- ruff linting (zero warnings)
- mypy strict type checking
- GitHub Actions CI on Python 3.9+

Removed:
- 700-line God class (Model)
- Monetization/subscription/payment/license system
- ML predictor, dashboard, API server
- Hardcoded token lists
- Python files as config
- Text file logging
- Floating-point financial math
- Thread-based concurrency
- 29 unnecessary dependencies (torch, sklearn, flask, stripe, etc.)