fix: 添加 hash_password 导入修复注册接口

- 注册时使用 hash_password 但未导入该函数
- 导致 NameError: name 'hash_password' is not defined

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/vitals/web/app.py

@@ -15,7 +15,7 @@ from uuid import uuid4
 
 from ..core import database as db
 from ..core.models import Exercise, Meal, Sleep, UserConfig, Weight, User, Reading, Invite
-from ..core.auth import verify_password, create_token, decode_token, generate_invite_code, get_token_expire_seconds
+from ..core.auth import hash_password, verify_password, create_token, decode_token, generate_invite_code, get_token_expire_seconds
 
 # 初始化数据库
 db.init_db()