Fix code formatting and linting issues

- Auto-format all Python files with black and isort
- Remove unused imports with autoflake
- Fix flake8 issues (missing newlines, blank lines, etc.)
- Fix nonlocal/global scope issues in main.py
- Fix security.py import order (E402)
- Remove f-string without placeholders
- Add nosec comment for intentional exception handling
- Fix test imports to match refactored DMARCParser API

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

backend/app/core/config.py

@@ -1,12 +1,12 @@
-from functools import lru_cache
-from typing import Optional, List, Union
-import secrets
 import logging
+import secrets
+from functools import lru_cache
+from typing import List, Optional, Union
 
 # Try to import from pydantic_settings first (newer versions)
 try:
-    from pydantic_settings import BaseSettings
     from pydantic import EmailStr, validator
+    from pydantic_settings import BaseSettings
 except ImportError:
     # Fall back to older pydantic version
     from pydantic import BaseSettings, EmailStr, validator
@@ -16,42 +16,42 @@ logger = logging.getLogger(__name__)
 
 class Settings(BaseSettings):
     """Application settings"""
-    
+
     # Base
     PROJECT_NAME: str = "DMARQ"
     API_V1_STR: str = "/api/v1"
-    
+
     # Database
     DATABASE_URL: str = "sqlite:///./dmarq.db"
-    
+
     # JWT Authentication
     SECRET_KEY: Optional[str] = None
     ALGORITHM: str = "HS256"
     ACCESS_TOKEN_EXPIRE_MINUTES: int = 60  # 1 hour
-    
+
     # CORS
     BACKEND_CORS_ORIGINS: List[str] = ["http://localhost:3000", "http://localhost:5173"]
-    
+
     # IMAP Settings
     IMAP_SERVER: Optional[str] = None
     IMAP_PORT: int = 993
     IMAP_USERNAME: Optional[str] = None
     IMAP_PASSWORD: Optional[str] = None
-    
+
     # Admin User
     FIRST_SUPERUSER: Optional[EmailStr] = None
     FIRST_SUPERUSER_PASSWORD: Optional[str] = None
-    
+
     # Optional Cloudflare Integration
     CLOUDFLARE_API_TOKEN: Optional[str] = None
     CLOUDFLARE_ZONE_ID: Optional[str] = None
-    
+
     @validator("SECRET_KEY", pre=True, always=True)
     def validate_secret_key(cls, v: Optional[str]) -> str:
         """Validate and generate SECRET_KEY if not provided."""
         # Default insecure key that should never be used
         DEFAULT_INSECURE_KEY = "CHANGE_THIS_TO_A_RANDOM_SECRET_IN_PRODUCTION"
-        
+
         if v is None or v == "" or v == DEFAULT_INSECURE_KEY:
             # Generate a secure random key
             generated_key = secrets.token_hex(32)
@@ -59,19 +59,19 @@ class Settings(BaseSettings):
                 "SECRET_KEY not configured or using default value! "
                 "Generated a random key for this session. "
                 "For production, set SECRET_KEY in your .env file using: "
-                f"openssl rand -hex 32"
+                "openssl rand -hex 32"
             )
             return generated_key
-        
+
         # Check if key is too short
         if len(v) < 32:
             logger.warning(
                 f"SECRET_KEY is too short ({len(v)} characters). "
                 "Recommended minimum is 32 characters for security."
             )
-        
+
         return v
-    
+
     @validator("BACKEND_CORS_ORIGINS", pre=True)
     def assemble_cors_origins(cls, v: Union[str, List[str]]) -> List[str]:
         if isinstance(v, str) and not v.startswith("["):
@@ -79,7 +79,7 @@ class Settings(BaseSettings):
         elif isinstance(v, (list, str)):
             return v
         raise ValueError(v)
-    
+
     class Config:
         env_file = ".env"
         case_sensitive = True
@@ -90,4 +90,4 @@ def get_settings() -> Settings:
     """
     Get application settings from environment variables or .env file
     """
-    return Settings()
+    return Settings()