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/domain/repositories/__init__.py

@@ -0,0 +1,10 @@
+"""Domain repository interfaces package."""
+from .player_repository import PlayerRepository
+from .team_repository import TeamRepository
+from .fantasy_repository import FantasyRepository
+
+__all__ = [
+    "PlayerRepository",
+    "TeamRepository",
+    "FantasyRepository",
+]

src/domain/repositories/fantasy_repository.py

@@ -0,0 +1,31 @@
+"""Fantasy team repository interface."""
+from abc import ABC, abstractmethod
+from typing import List, Optional
+
+from src.domain.entities import FantasyTeam
+
+
+class FantasyRepository(ABC):
+    """Abstract interface for Yahoo Fantasy Hockey data access."""
+
+    @abstractmethod
+    async def get_fantasy_team(
+        self, league_id: str, team_id: str
+    ) -> Optional[FantasyTeam]:
+        """Retrieves a specific fantasy team from a league."""
+        pass
+
+    @abstractmethod
+    async def get_user_teams(self, user_id: str) -> List[FantasyTeam]:
+        """Retrieves all fantasy teams for a user."""
+        pass
+
+    @abstractmethod
+    async def get_team_roster(self, league_id: str, team_id: str) -> List[str]:
+        """Retrieves the player IDs on a fantasy team's roster."""
+        pass
+
+    @abstractmethod
+    async def get_league_standings(self, league_id: str) -> List[FantasyTeam]:
+        """Retrieves all teams in a league ordered by standings."""
+        pass

src/domain/repositories/player_repository.py

@@ -0,0 +1,36 @@
+"""Player repository interface."""
+from abc import ABC, abstractmethod
+from typing import List, Optional
+
+from src.domain.entities import Player, SkaterStats, GoalieStats
+
+
+class PlayerRepository(ABC):
+    """Abstract interface for player data access."""
+
+    @abstractmethod
+    async def get_player_by_id(self, player_id: str) -> Optional[Player]:
+        """Retrieves a player by their unique identifier."""
+        pass
+
+    @abstractmethod
+    async def get_players_by_team(self, team_id: str) -> List[Player]:
+        """Retrieves all players for a specific team."""
+        pass
+
+    @abstractmethod
+    async def search_players(
+        self, name: str, position: Optional[str] = None
+    ) -> List[Player]:
+        """Searches for players by name and optionally by position."""
+        pass
+
+    @abstractmethod
+    async def get_skater_stats(self, player_id: str) -> Optional[SkaterStats]:
+        """Retrieves current season statistics for a skater."""
+        pass
+
+    @abstractmethod
+    async def get_goalie_stats(self, player_id: str) -> Optional[GoalieStats]:
+        """Retrieves current season statistics for a goalie."""
+        pass

src/domain/repositories/team_repository.py

@@ -0,0 +1,29 @@
+"""Team repository interface."""
+from abc import ABC, abstractmethod
+from typing import List, Optional
+
+from src.domain.entities import NHLTeam
+
+
+class TeamRepository(ABC):
+    """Abstract interface for NHL team data access."""
+
+    @abstractmethod
+    async def get_team_by_id(self, team_id: str) -> Optional[NHLTeam]:
+        """Retrieves a team by its unique identifier."""
+        pass
+
+    @abstractmethod
+    async def get_all_teams(self) -> List[NHLTeam]:
+        """Retrieves all NHL teams."""
+        pass
+
+    @abstractmethod
+    async def get_teams_by_division(self, division: str) -> List[NHLTeam]:
+        """Retrieves all teams in a specific division."""
+        pass
+
+    @abstractmethod
+    async def get_teams_by_conference(self, conference: str) -> List[NHLTeam]:
+        """Retrieves all teams in a specific conference."""
+        pass