fix(mobile): tame selection handle page advance

[codedogQBY]

Summary

• Let Foliate's built-in paginated selection handler drive cross-page selection on mobile instead of running a second ReadAny page-advance monitor.
• Stop locking Foliate navigation merely because RN has an active text selection; that lock also disables Foliate's official selection auto-page path.
• Make Foliate's pointer-selection auto-page work better on Android handles by:
  • using the selection document to detect selection direction across iframe content;
  • throttling active drag checks instead of waiting for a trailing debounce;
  • triggering a page turn when the active selection edge reaches the visible page edge, even if Android clamps the Range at the current page boundary;
  • requiring a stable 1s dwell at the page edge before that edge fallback turns the page;
  • resetting that dwell whenever the selection Range changes or any available touch/pointer point keeps moving;
  • allowing selectionchange itself to drive paging on touch devices, because Android native selection handles do not always expose reliable pointer button/edge coordinates to the iframe;
  • using touch/pointer coordinates only as movement reset signals, not as hard requirements for paging;
  • canceling the pending edge turn on pointer/touch release;
  • narrowing the edge activation zone and removing the vertical top/bottom fallback to reduce accidental turns;
  • guarding against overlapping page turns.
• Keep ReadAny selection reporting/tap suppression, and rebuild the Expo reader bundle.

Root Cause

Foliate already supports cross-page selection in foliate-paginator: while pointer-selecting, selectionchange compares the current selection with the last visible range and calls next()/prev() when the selection crosses the page boundary.

ReadAny was blocking or weakening that path in several ways:

• RN called window.setNavigationLocked(true) whenever selection was active, but Foliate's selection paging exits early when navigationLocked is true.
• The reader injected its own cross-page selection monitor, locking paginator container scrolling and competing with Foliate's native selection relocation behavior.
• Android selection handles can clamp the Range at the visible page edge instead of extending it past lastVisibleRange, so Foliate's original strict range-boundary comparison never fired.
• The original direction check used the outer document to create a Range for iframe content, which can fail in WebView.
• Requiring the touch/pointer point itself to be at the page edge was too strict on Android WebView; the native selection handle can update the selection without exposing matching pointer coordinates.

Validation

• pnpm --filter @readany/app-expo run build:reader
• pnpm --filter @readany/app-expo exec tsc --noEmit
• git diff --check

Fixes #287