Fix Pydantic Settings validation error for extra environment variables

- Added CONTENT field to Settings model with Optional type
- Set extra='ignore' in Config to allow extra environment variables
- Added the same config to custom BaseSettings implementation for consistency
- Added missing import for Optional type

app/core/config.py

@@ -1,5 +1,6 @@
 import os
 from pathlib import Path
+from typing import Optional
 
 from pydantic import BaseModel
 
@@ -16,6 +17,7 @@ except ImportError:
         class Config:
             env_file = ".env"
             case_sensitive = True
+            extra = "ignore"  # Allow extra fields from environment variables
 
         def __init__(self, **kwargs):
             # Load environment variables
@@ -38,9 +40,13 @@ class Settings(BaseSettings):
     DB_DIR: Path = Path("/app") / "storage" / "db"
     DB_NAME: str = "db.sqlite"
     
+    # Environment variables that can be accessed via API
+    CONTENT: Optional[str] = None
+    
     class Config:
         env_file = ".env"
         case_sensitive = True
+        extra = "ignore"  # Allow extra fields from environment variables
 
 
 settings = Settings()