feat: initial Pyramid project scaffold

lib/features/chat/chat_page.dart

@@ -0,0 +1,14 @@
+import 'package:flutter/material.dart';
+
+class ChatPage extends StatelessWidget {
+  final String roomId;
+  const ChatPage({super.key, required this.roomId});
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: Text(roomId)),
+      body: const Center(child: Text('Chat')),
+    );
+  }
+}