please add highlighter and bookmark features

[EinsteinDGreat]

Please, follow all of these checks (Issues that do not will be canceled):

• This feature is not implemented and does not have opened/closed Issues.
• I propose ONLY one feature at a time. One feature - one Issue.
• I use English. This repository's language is English.
• I properly filled the template below(not necessarily all parts, but at least first two).
• I did not use any placeholder such as [Feature] or [Bug] in the title of the Issue.

Why you want this feature to be implemented? Please describe.
right now, there’s no way to highlight or save important parts while reading. this makes it really hard to keep track of key information, especially for studying or note-taking. having these features would make reading and reviewing so much easier.

Describe the feature you'd like to be implemented
a highlighter that lets users mark important sentences or paragraphs and a bookmark feature to save specific pages or locations in the text. this way, users can quickly jump back to key sections instead of searching manually.

Describe alternatives you've considered
right now, the only option is to take screenshots or copy text somewhere else, which is not ideal. it would be much better to have these features built into the app.

Additional context
these features are standard in many reading apps and would improve the experience a lot. would love to see them added please

[Acclorite]

Duplicate of #20 and #111