design: Big redesign of three column mode to advanced two column mode

lib/pages/chat_members/chat_members.dart

@@ -0,0 +1,76 @@
+import 'package:flutter/material.dart';
+
+import 'package:matrix/matrix.dart';
+
+import '../../widgets/matrix.dart';
+import 'chat_members_view.dart';
+
+class ChatMembersPage extends StatefulWidget {
+  final String roomId;
+  const ChatMembersPage({required this.roomId, super.key});
+
+  @override
+  State<ChatMembersPage> createState() => ChatMembersController();
+}
+
+class ChatMembersController extends State<ChatMembersPage> {
+  List<User>? members;
+  List<User>? filteredMembers;
+  Object? error;
+
+  final TextEditingController filterController = TextEditingController();
+
+  void setFilter([_]) async {
+    final filter = filterController.text.toLowerCase().trim();
+
+    if (filter.isEmpty) {
+      setState(() {
+        filteredMembers = members
+          ?..sort((b, a) => a.powerLevel.compareTo(b.powerLevel));
+      });
+      return;
+    }
+    setState(() {
+      filteredMembers = members
+          ?.where(
+            (user) =>
+                user.displayName?.toLowerCase().contains(filter) ??
+                user.id.toLowerCase().contains(filter),
+          )
+          .toList()
+        ?..sort((b, a) => a.powerLevel.compareTo(b.powerLevel));
+    });
+  }
+
+  void refreshMembers() async {
+    try {
+      setState(() {
+        error = null;
+      });
+      final participants = await Matrix.of(context)
+          .client
+          .getRoomById(widget.roomId)
+          ?.requestParticipants();
+
+      setState(() {
+        members = participants;
+      });
+      setFilter();
+    } catch (e, s) {
+      Logs()
+          .d('Unable to request participants. Try again in 3 seconds...', e, s);
+      setState(() {
+        error = e;
+      });
+    }
+  }
+
+  @override
+  void initState() {
+    super.initState();
+    refreshMembers();
+  }
+
+  @override
+  Widget build(BuildContext context) => ChatMembersView(this);
+}