Port PR #979's silent pre-indexing and add an Indexing Display setting
(Popup / Status Bar Text / Status Bar Icon) so users can choose how
indexing feedback is shown.
Silent pre-indexing runs on text-only penultimate pages when a status
bar option is selected, with a standard requestUpdate to clear the
indicator. Image pages skip silent indexing to avoid e-ink grayscale
pipeline conflicts; the normal popup handles those transitions. Direct
chapter jumps always show the original small popup regardless of setting.
Co-authored-by: Cursor <cursoragent@cursor.com>
426a978e44
