notes

Looks fine in light mode, text unreadable in dark mode.

Looks like getSelectedLayerId will insert a layer if there are no layers in the page. That's pretty undesirable imo, we should refactor it (perhaps in a followup) so that the page layers are always in a valid state.

Originally posted by @Technius in xournalpp/xournalpp#4025 (comment)

Which part of the project should be enhanced?
The MediaController in both the public and private APIs

Describe the solution you'd like
When uploading media, the ID of the note the upload belongs to is transferred in a header.
Currently, the business logic uses await this.noteService.getNoteByIdOrAlias(noteId); to create a Note instance from that. We should implement a custom para

There should be some kind of a slider for selecting a brush size instead of just buttons to adjust it. Maybe it doesn't have to be a visible slider but how Adobe does it: sliding with mouse over a number increases/decreases the number