✨ Introduce seasonal hero image collage feature

Add functionality to return contextually appropriate hero collage images based on the current date, including seasonal and holiday-specific images. Implement tests to ensure correct image selection and coverage. ✨ Add comparison pages for EmailToFuture and FutureMe Introduce new HTML pages comparing OhDiary with EmailToFuture and FutureMe, highlighting features, benefits, and use cases for each journaling tool.