Phase 2 of the reader redesign:
- Fixed-layout touch engine (foliate-js e9e61d8): pinch-zoom around
the midpoint, two-finger pan, single-finger pan while zoomed,
horizontal swipe page-turn at fit (RTL-aware via next()/prev()),
and double-tap to zoom 2.5x / reset. Touch events forwarded from
page iframes with converted coordinates; preventDefault only when
the engine consumes the gesture, so PDF text selection and native
taps stay intact. touch-action: none on the host and in comic/pdf
page documents keeps the browser from fighting the engine.
- Tap zones (Kindle-style) for touch devices: tap the outer margins
to page, center to toggle chrome. Size configurable (10-50%) via
the revived tap_zone_size setting; toggle via new tap_zones_enabled
(Behavior section of the settings drawer). Pointer-based + passive
so drags/swipes/selection never trigger; attached both to the
viewport and inside every page document (iframe events don't
bubble); debounced 280ms so double-tap zoom doesn't also page; no
zone actions while a fixed-layout page is zoomed.
- Drawers become full-width sheets on screens <= 640px.