Introduces a Christmas theme that activates in December, including themed colors, subtle background patterns, and snowflake effects on loading screens. Adds a reusable SnowLoader component and utility for December detection. Updates layout and loading components to conditionally apply decorations and styles only during December.
Dynamically import ChatDetail, NewChatForm, and ProductSelector components with skeleton loading states for improved performance. Refine product selection logic in promotion forms to show blacklist selector only for 'all' mode and clarify labels and descriptions for better user understanding.
