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/files_view.dart

@@ -853,14 +853,30 @@ class _FilesViewState extends State<FilesView> {
             unawaited(sync.syncOnPull());
             return browser.reload();
           },
-          child: CustomScrollView(
-            controller: widget.scrollController,
-            // Pull-to-refresh needs a scroll physics that allows dragging
-            // past the edge even when content doesn't fill the viewport -
-            // an empty or single-item list otherwise can't be pulled at all
-            // under the platform default physics.
-            physics: const AlwaysScrollableScrollPhysics(),
-            slivers: contentSlivers,
+          // `topBarSliver`'s floating header can collapse all the way to
+          // zero height (fully scrolled away), at which point the sticky
+          // controls row right below it in `contentSlivers` would otherwise
+          // ride up underneath the status bar instead of stopping below it
+          // - the floating top bar used to be the only thing reserving that
+          // space (via its own internal `SafeArea`), and that reservation
+          // disappears along with it once it's fully hidden. Wrapping the
+          // whole scroll view keeps the inset outside the scrolling region
+          // entirely, so it's never implicated in the floating header's own
+          // collapse/reveal math - safe to apply unconditionally, since
+          // desktop's `MediaQuery.padding.top` is 0 anyway (no topBar / no
+          // status bar there).
+          child: SafeArea(
+            top: true,
+            bottom: false,
+            child: CustomScrollView(
+              controller: widget.scrollController,
+              // Pull-to-refresh needs a scroll physics that allows dragging
+              // past the edge even when content doesn't fill the viewport -
+              // an empty or single-item list otherwise can't be pulled at
+              // all under the platform default physics.
+              physics: const AlwaysScrollableScrollPhysics(),
+              slivers: contentSlivers,
+            ),
           ),
         ),
       ),