feat(api): add REST endpoints

src/arbiter/api/deps.py

@@ -0,0 +1,54 @@
+"""FastAPI dependency injection for Arbiter."""
+
+from collections.abc import AsyncGenerator
+from functools import lru_cache
+from typing import Annotated
+
+from fastapi import Depends
+from redis.asyncio import Redis
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from arbiter.config import Settings
+from arbiter.config import get_settings as _get_settings
+from arbiter.db.session import get_async_session
+
+# Redis client cache
+_redis_client: Redis | None = None
+
+
+@lru_cache
+def get_settings() -> Settings:
+    return _get_settings()
+
+
+async def get_db() -> AsyncGenerator[AsyncSession, None]:
+    async for session in get_async_session():
+        yield session
+
+
+async def get_redis() -> AsyncGenerator[Redis, None]:
+    """Get Redis client dependency."""
+    global _redis_client
+    settings = get_settings()
+
+    if _redis_client is None:
+        _redis_client = Redis.from_url(
+            settings.redis_url,
+            max_connections=settings.redis_max_connections,
+            decode_responses=True,
+        )
+
+    yield _redis_client
+
+
+async def close_redis() -> None:
+    global _redis_client
+    if _redis_client is not None:
+        await _redis_client.close()
+        _redis_client = None
+
+
+# Type aliases for cleaner route signatures
+DbSession = Annotated[AsyncSession, Depends(get_db)]
+RedisClient = Annotated[Redis, Depends(get_redis)]
+AppSettings = Annotated[Settings, Depends(get_settings)]