fix(ui): square mobile file tiles, files scroll clearance, apps-tab swipe guard

- Apps tab: a horizontal swipe that starts on an app icon no longer flips the
  top tab — it lets the app-page scroll / icon tap win (swipe empty space to
  change tab). Fixes the swipe conflict with two pages of apps.
- Files: file cover tiles are forced square on mobile (aspect driven by CSS,
  not a Tailwind arbitrary class) so the grid is uniform and tappable.
- Files: scroll container gets bottom safe-area + tab-bar padding so the last
  row clears the mobile back button / bottom nav.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

neode-ui/src/style.css

@@ -1827,6 +1827,22 @@ html.modal-scroll-locked .dashboard-scroll-panel {
   }
 }
 
+/* Mobile: square, tappable tiles + bottom clearance so the last row scrolls
+   above the tab bar / back button (matches .mobile-scroll-pad). */
+@media (max-width: 767px) {
+  .cloud-card-grid,
+  .cloud-file-list {
+    padding-bottom: calc(
+      var(--mobile-tab-bar-height, 88px) +
+      var(--safe-area-bottom, env(safe-area-inset-bottom, 0px)) +
+      var(--audio-player-height, 0px) + 24px
+    );
+  }
+  .cloud-grid-card-cover {
+    aspect-ratio: 1 / 1;
+  }
+}
+
 .cloud-grid-card {
   display: flex;
   flex-direction: column;
@@ -1856,6 +1872,9 @@ html.modal-scroll-locked .dashboard-scroll-panel {
 .cloud-grid-card-cover {
   position: relative;
   width: 100%;
+  /* Fallback aspect when the Tailwind aspect-[4/3] utility is unavailable, so
+     the cover never collapses to zero height. */
+  aspect-ratio: 4 / 3;
   overflow: hidden;
   border-radius: 0.625rem;
 }