Initial commit: CLEAN architecture foundation for fantasy hockey backend

Implemented CLEAN architecture with clear separation of concerns:
- Domain layer with entities (Player, Team, Stats, FantasyTeam) and repository interfaces
- Application layer with use case implementations
- Infrastructure layer with NHL API and Yahoo Fantasy API adapters
- Presentation layer with FastAPI configuration and dependency injection

Key features:
- Swappable data source adapters (NHL API, Yahoo Fantasy API)
- Repository pattern for data access abstraction
- Dependency injection for loose coupling
- FastAPI framework with async support
- PostgreSQL database configuration
- Environment-based configuration management

Technology stack: Python 3.11+, FastAPI, PostgreSQL, nhl-api-py, yfpy

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

requirements.txt

@@ -0,0 +1,26 @@
+# Web Framework
+fastapi==0.115.5
+uvicorn[standard]==0.32.1
+pydantic==2.10.3
+pydantic-settings==2.6.1
+
+# Database
+sqlalchemy==2.0.36
+asyncpg==0.30.0
+alembic==1.14.0
+
+# External APIs
+nhl-api-py==1.1.0
+yfpy==14.1.1
+
+# Utilities
+python-dotenv==1.0.1
+httpx==0.28.1
+
+# Development
+pytest==8.3.4
+pytest-asyncio==0.24.0
+pytest-cov==6.0.0
+black==24.10.0
+ruff==0.8.4
+mypy==1.13.0