Fix article-view swipe being swallowed by Chrome-on-Android back gesture

On real Android touchscreens, a horizontal drag on content with nothing
left to scroll horizontally gets claimed by Chrome's native
swipe-to-go-back/forward gesture before our own touchend listener
(article-view swipe navigation) ever sees it — silently, with no
touchend firing at all. Synthetic touch testing (mouse-drag emulation
in devtools) doesn't go through that gesture recognizer, so it worked
there while doing nothing on an actual phone.

Fix: overscroll-behavior-x: contain on body stops Chrome from claiming
the gesture for its own navigation, letting our touchend fire normally.

Also drops the overflow-x: hidden added to .article-single for the
slide transition — body already has it (for the same full-bleed-image
reason), so it was redundant.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

vue/src/assets/base.css

@@ -81,6 +81,12 @@ body {
      wider than the visible content area (scrollbar) and would otherwise
      introduce a horizontal scrollbar. */
   overflow-x: hidden;
+  /* Without this, a horizontal touch drag on content with nothing left to
+     scroll (true here, given overflow-x: hidden above) is claimed by
+     Chrome-on-Android's native swipe-to-go-back/forward gesture before our
+     own touchend listener (article-view swipe navigation) ever sees it —
+     the gesture is silently swallowed with no error, no touchend fires. */
+  overscroll-behavior-x: contain;
   color: var(--color-text);
   background: var(--color-background);
   transition: color 0.5s, background-color 0.5s;

vue/src/components/RssFeeds.vue

@@ -367,7 +367,6 @@ onMounted(async () => {
   align-items: center;
   padding-top: 1em;
   padding-bottom: 5rem;
-  overflow-x: hidden;
 }
 
 .article-feature {