feat: add unified linting scripts and git hooks for code quality enforcement

- Introduced `lint` and `lint-fix` applications in `flake.nix` for unified linting of backend (Python) and frontend (TypeScript/Svelte) code.
- Added `scripts/lint.sh` for manual linting execution.
- Created `scripts/install-hooks.sh` to set up git hooks for automatic linting before commits and optional tests before pushes.
- Updated `README.md` with instructions for using the new linting features and git hooks.

backend/app/auth/jwt.py

@@ -1,6 +1,6 @@
 """JWT token generation and validation."""
+
 from datetime import datetime, timedelta
-from typing import Optional
 from uuid import UUID
 
 from jose import JWTError, jwt
@@ -8,15 +8,15 @@ from jose import JWTError, jwt
 from app.core.config import settings
 
 
-def create_access_token(user_id: UUID, email: str, expires_delta: Optional[timedelta] = None) -> str:
+def create_access_token(user_id: UUID, email: str, expires_delta: timedelta | None = None) -> str:
     """
     Create a new JWT access token.
-    
+
     Args:
         user_id: User's UUID
         email: User's email address
         expires_delta: Optional custom expiration time
-        
+
     Returns:
         Encoded JWT token string
     """
@@ -24,26 +24,20 @@ def create_access_token(user_id: UUID, email: str, expires_delta: Optional[timed
         expire = datetime.utcnow() + expires_delta
     else:
         expire = datetime.utcnow() + timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
-    
-    to_encode = {
-        "sub": str(user_id),
-        "email": email,
-        "exp": expire,
-        "iat": datetime.utcnow(),
-        "type": "access"
-    }
-    
+
+    to_encode = {"sub": str(user_id), "email": email, "exp": expire, "iat": datetime.utcnow(), "type": "access"}
+
     encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
     return encoded_jwt
 
 
-def decode_access_token(token: str) -> Optional[dict]:
+def decode_access_token(token: str) -> dict | None:
     """
     Decode and validate a JWT access token.
-    
+
     Args:
         token: JWT token string to decode
-        
+
     Returns:
         Decoded token payload if valid, None otherwise
     """
@@ -52,4 +46,3 @@ def decode_access_token(token: str) -> Optional[dict]:
         return payload
     except JWTError:
         return None
-