Fix status-bar overlap on scroll, and reposition/elevate the avatar menu

- Every tab now wraps its CustomScrollView in SafeArea(top: true) - the
  pinned sort/filter row was riding up underneath the status bar once
  the floating top bar above it fully collapsed, since that bar's own
  internal SafeArea only reserved the inset while it had some height
  left to put it in. Reserving it outside the scrolling region entirely
  fixes this regardless of the floating header's state. Caught live on
  device and backed by a new regression test.
- The avatar menu now covers the top bar (title included) instead of
  sitting below it - positioned off just the status-bar inset rather
  than the top bar's full height on top of that.
- The avatar menu's card now carries a second, tighter contact shadow
  alongside nooDialogShadow - that shadow alone was essentially
  invisible on a small card over a dark theme's near-black background.

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

lib/views/shares_view.dart

@@ -134,12 +134,19 @@ class _SharesViewState extends State<SharesView> {
         color: colors.accent,
         backgroundColor: colors.surface,
         onRefresh: sharesController.fetchAll,
-        child: CustomScrollView(
-          controller: widget.scrollController,
-          // See files_view.dart's identical fix - without this, pull-to-
-          // refresh can't be triggered on an empty or single-item list.
-          physics: const AlwaysScrollableScrollPhysics(),
-          slivers: contentSlivers,
+        // See files_view.dart's identical fix - without this, the sticky
+        // controls row rides up under the status bar once the floating top
+        // bar above it fully collapses.
+        child: SafeArea(
+          top: true,
+          bottom: false,
+          child: CustomScrollView(
+            controller: widget.scrollController,
+            // See files_view.dart's identical fix - without this, pull-to-
+            // refresh can't be triggered on an empty or single-item list.
+            physics: const AlwaysScrollableScrollPhysics(),
+            slivers: contentSlivers,
+          ),
         ),
       ),
     );