refactor: remove Redis dependency and related code

backend/app/core/config.py

@@ -12,7 +12,6 @@ class Settings(BaseSettings):
 
     MONGODB_URI: str
     MONGODB_DB_NAME: str
-    REDIS_URL: str
     JWT_SECRET_KEY: str
     JWT_ALGORITHM: str = "HS256"
     JWT_EXPIRE_MINUTES: int = Field(default=720, gt=0)

backend/app/core/redis.py

@@ -1,22 +0,0 @@
-import redis.asyncio as aioredis
-from core.config import settings
-
-_redis_pool: aioredis.Redis | None = None
-
-
-async def init_redis() -> None:
-    global _redis_pool
-    _redis_pool = aioredis.from_url(
-        settings.REDIS_URL, encoding="utf-8", decode_responses=True
-    )
-
-
-async def close_redis() -> None:
-    if _redis_pool:
-        await _redis_pool.aclose()
-
-
-async def get_redis() -> aioredis.Redis:
-    if _redis_pool is None:
-        raise RuntimeError("Redis pool has not been initialized")
-    return _redis_pool