refactor(recipes): introduce dedicated services for handlers

py/services/recipes/errors.py

@@ -0,0 +1,22 @@
+"""Shared exceptions for recipe services."""
+from __future__ import annotations
+
+
+class RecipeServiceError(Exception):
+    """Base exception for recipe service failures."""
+
+
+class RecipeValidationError(RecipeServiceError):
+    """Raised when a request payload fails validation."""
+
+
+class RecipeNotFoundError(RecipeServiceError):
+    """Raised when a recipe resource cannot be located."""
+
+
+class RecipeDownloadError(RecipeServiceError):
+    """Raised when remote recipe assets cannot be downloaded."""
+
+
+class RecipeConflictError(RecipeServiceError):
+    """Raised when a conflicting recipe state is detected."""