* Refactor chapter filtering and auto-save logic
Simplified chapter filtering to only exclude empty titles, allowing default chapter names. Updated auto-save logic to skip saving when there are no chapters or mediaId. Removed unused helper function and improved debug logging.
* Show default chapter title in editor and set initial title
The chapter title is now always displayed in the textarea, including default names like 'Chapter 1'. Also, the initial segment is created with 'Chapter 1' as its title instead of an empty string for better clarity.
* build assets
