Remove unused service protocol aliases and use direct service imports

backend/app/routers/auth.py

@@ -12,14 +12,9 @@ from __future__ import annotations
 import structlog
 from fastapi import APIRouter, HTTPException, Request, Response, status
 
-from app.dependencies import (
-    AuthServiceDep,
-    DbDep,
-    SessionCacheDep,
-    SessionRepoDep,
-    SettingsDep,
-)
+from app.dependencies import DbDep, SessionCacheDep, SessionRepoDep, SettingsDep
 from app.models.auth import LoginRequest, LoginResponse, LogoutResponse
+from app.services import auth_service
 from app.utils.constants import SESSION_COOKIE_NAME
 
 log: structlog.stdlib.BoundLogger = structlog.get_logger()
@@ -37,7 +32,6 @@ async def login(
     response: Response,
     db: DbDep,
     settings: SettingsDep,
-    auth_service: AuthServiceDep,
     session_repo: SessionRepoDep,
 ) -> LoginResponse:
     """Verify the master password and return a session token.
@@ -93,7 +87,6 @@ async def logout(
     db: DbDep,
     settings: SettingsDep,
     session_cache: SessionCacheDep,
-    auth_service: AuthServiceDep,
     session_repo: SessionRepoDep,
 ) -> LogoutResponse:
     """Invalidate the active session.