Use a session-wide byte-accounted LRU instead of retaining every visited
page. Share the renderer's PageText Arc without cloning all glyphs and
avoid retaining obsolete document bytes through the cache.
Preserve per-page extraction results so text_find can continue after a
failed page, reporting bounded warnings alongside readable matches and
normal continuation cursors. Other text consumers retain strict errors.
Add deterministic coverage for cache budgets across documents, eviction,
revision changes, close, partial searches and bounded warnings.
Fixes#1483.
Co-authored-by: LabDennis <341377186+LabDennis@users.noreply.github.com>
