feat: Migrate to Pydantic's @field_validator and implement lifespan handler in FastAPI

scripts/init_db.py

@@ -22,7 +22,7 @@ import os
 import logging
 from decimal import Decimal
 
-from pydantic import BaseModel, Field, validator
+from pydantic import BaseModel, Field, field_validator
 from sqlalchemy import create_engine, text
 from sqlalchemy.engine import Engine
 from passlib.context import CryptContext
@@ -454,7 +454,7 @@ class UserSeed(BaseModel):
     is_active: bool = True
     is_superuser: bool = False
 
-    @validator("password")
+    @field_validator("password")
     def password_min_len(cls, v: str) -> str:
         if not v or len(v) < 8:
             raise ValueError("password must be at least 8 characters")