Remove scrollbar thumb and restructure Settings profile card

- Revert the scrollbar-thumb feature entirely (per-view Scrollbar
  wrappers and the ScrollbarThemeData override) - back to plain
  scrollables with no visible thumb
- Settings: move the logout button into the profile card (next to the
  name/email), and move the ONLINE/OFFLINE badge + "Connected to..."
  text out of the top row into a combined line at the bottom of the
  card, instead of split between the AppBar and the top of the screen
- Update architecture.md/styling.md to drop the stale scrollbar-theme
  documentation

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

lib/views/search_view.dart

@@ -18,7 +18,6 @@ class SearchView extends StatefulWidget {
 class _SearchViewState extends State<SearchView> {
   final _controller = TextEditingController();
   final _focusNode = FocusNode();
-  final _resultsScrollController = ScrollController();
   Timer? _debounce;
 
   List<NextcloudItem> _results = [];
@@ -31,7 +30,6 @@ class _SearchViewState extends State<SearchView> {
     _debounce?.cancel();
     _controller.dispose();
     _focusNode.dispose();
-    _resultsScrollController.dispose();
     super.dispose();
   }
 
@@ -187,32 +185,24 @@ class _SearchViewState extends State<SearchView> {
         ),
       );
     }
-    return Scrollbar(
-      controller: _resultsScrollController,
-      child: ListView.builder(
-        controller: _resultsScrollController,
-        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
-        itemCount: _results.length,
-        itemBuilder: (context, index) {
-          final item = _results[index];
-          return ListTile(
-            leading: Icon(_iconFor(item.type), color: colorScheme.primary),
-            title: Text(
-              item.name,
-              maxLines: 1,
-              overflow: TextOverflow.ellipsis,
-            ),
-            subtitle: Text(
-              item.isFolder
-                  ? item.path
-                  : DateFormat.yMMMd().format(item.lastModified),
-              maxLines: 1,
-              overflow: TextOverflow.ellipsis,
-            ),
-            onTap: () => _openResult(item),
-          );
-        },
-      ),
+    return ListView.builder(
+      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
+      itemCount: _results.length,
+      itemBuilder: (context, index) {
+        final item = _results[index];
+        return ListTile(
+          leading: Icon(_iconFor(item.type), color: colorScheme.primary),
+          title: Text(item.name, maxLines: 1, overflow: TextOverflow.ellipsis),
+          subtitle: Text(
+            item.isFolder
+                ? item.path
+                : DateFormat.yMMMd().format(item.lastModified),
+            maxLines: 1,
+            overflow: TextOverflow.ellipsis,
+          ),
+          onTap: () => _openResult(item),
+        );
+      },
     );
   }
 }