Fix accidental page-swipe while scrolling; bring linked-article reader to parity

- ReaderScreen: HorizontalPager's full-surface drag detection was treating
  ordinary vertical scrolling inside the embedded WebView (a native View,
  which doesn't arbitrate with Compose's gesture system the way a
  pure-Compose scrollable child would) as an attempted horizontal page-turn
  on anything less than a perfectly vertical swipe -- i.e. most real thumb
  scrolling. Tried gating it to edge-zone-only drags first, but that
  collides with Android's own edge-swipe-back gesture on gesture-nav
  devices (reproduced live: an edge swipe triggered system back, not the
  pager). Landed on disabling the Pager's built-in gesture and driving it
  from a custom detector that works anywhere on screen but only commits to
  a page turn once a drag is clearly horizontal-dominant (>2x the vertical
  movement) -- ordinary scrolling, even sloppy/diagonal, is left completely
  unconsumed for the WebView. Verified live: a deliberately diagonal
  mid-screen scroll now stays on the same article; a decisive horizontal
  swipe still changes pages.

- LinkReaderScreen: was missing the bookmark/Stash/reader-toggle/menu
  actions entirely -- reported after tapping a link left "all my icons...
  gone." Brought to parity with the main article reader: save locally and
  save to Stash now lazily create a standalone ArticleEntity (feedId=null,
  id = hash of the URL, same scheme ShareReceiverActivity uses) on first
  use; reader-mode toggle falls back to the live page (JS on) instead of
  always forcing extraction; same login/find-another-source menu. Verified
  live: all 5 icons present once extraction finishes, bookmarking a linked
  article correctly creates a standalone DB row.

0 files changed, 0 insertions, 0 deletions