feat: enhance invoice validation and error handling with detailed messages

backend/core/error_handlers.py

@@ -31,6 +31,10 @@ async def base_exception_handler(
         },
     )
 
+    # Log detailed errors if they exist
+    if hasattr(exc, "errors") and exc.errors:
+        logger.warning(f"Validation errors details: {exc.errors}")
+
     return JSONResponse(
         status_code=exc.status_code,
         content=exc.to_dict(),