Refactor password handling and model typing

Replaced custom password generation and verification logic with a new pkg/password.py module using Argon2 for secure hashing. Updated model field types to use PEP 604 union syntax (e.g., str | None) and improved type annotations. Refactored admin and session routes to use new password utilities and direct model methods for CRUD operations. Removed legacy tool-based password functions and cleaned up .idea project files.

model/response.py

@@ -1,5 +1,5 @@
 from pydantic import BaseModel
-from typing import Literal, Optional
+from typing import Literal
 
 class DefaultResponse(BaseModel):
     code: int = 0