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>

src/presentation/api/dependencies.py

@@ -0,0 +1,47 @@
+"""FastAPI dependency injection configuration."""
+from functools import lru_cache
+
+from src.domain.repositories import PlayerRepository, TeamRepository, FantasyRepository
+from src.infrastructure.adapters.nhl import NHLPlayerAdapter, NHLTeamAdapter
+from src.infrastructure.adapters.yahoo_fantasy import YahooFantasyAdapter
+from src.infrastructure.config import Settings, get_settings
+
+
+@lru_cache()
+def get_cached_settings() -> Settings:
+    """Returns cached application settings."""
+    return get_settings()
+
+
+def get_player_repository() -> PlayerRepository:
+    """
+    Provides the PlayerRepository implementation.
+
+    This function can be modified to return different implementations
+    without changing any business logic or API code.
+    """
+    return NHLPlayerAdapter()
+
+
+def get_team_repository() -> TeamRepository:
+    """
+    Provides the TeamRepository implementation.
+
+    This function can be modified to return different implementations
+    without changing any business logic or API code.
+    """
+    return NHLTeamAdapter()
+
+
+def get_fantasy_repository() -> FantasyRepository:
+    """
+    Provides the FantasyRepository implementation.
+
+    This function can be modified to return different implementations
+    without changing any business logic or API code.
+    """
+    settings = get_cached_settings()
+    return YahooFantasyAdapter(
+        consumer_key=settings.yahoo_consumer_key,
+        consumer_secret=settings.yahoo_consumer_secret,
+    )