Auto-enumeration for Titles/Subtitles

Add an option to automatically enumerate titles within the app. This might improve clarity by making the hierarchy of page titles and subtitles easier to understand.

When enabled, titles should be prefixed with automatically generated numbers based on their position in the document hierarchy. Nested title levels should follow hierarchical numbering.

Examples:
1. Title
2. Title
2.1. Subtitle
2.2. Subtitle
2.2.a. Subsubtitle
2.2.b. Subsubtitle
3. Title

<img width="1920" height="911" alt="example-auto-enumeration" src=" />