Flutter 앱 골격 · 5탭 네비게이션 · 로그인 화면 · Firestore 보안 규칙·인덱스

app/lib/features/inside/inside_screen.dart

@@ -0,0 +1,16 @@
+import 'package:flutter/material.dart';
+
+import '../../core/ui/tab_placeholder.dart';
+
+/// INSIDE 탭 루트 — S-I-LOUNGE 팬덤 라운지.
+class InsideScreen extends StatelessWidget {
+  const InsideScreen({super.key});
+
+  @override
+  Widget build(BuildContext context) => const TabPlaceholder(
+    tab: 'INSIDE',
+    screenId: 'S-I-LOUNGE',
+    screenName: '팬덤 라운지',
+    specPath: 'wireframe/planning/screen-spec/inside/S-I-LOUNGE.md',
+  );
+}