added landing page

app/pubspec.yaml

@@ -17,6 +17,7 @@ dependencies:
     sdk: flutter
   flutter_hooks: ^0.20.5
   flutter_inappwebview: ^6.0.0
+  flutter_markdown: ^0.7.1
   flutter_material_design_icons: ^1.1.7447
   flutter_pdf_text: ^0.6.0
   flutter_secure_storage: ^9.0.0
@@ -57,6 +58,7 @@ flutter:
   uses-material-design: true
   assets:
     - assets/icon/icon.png
+    - assets/landing/
 
 flutter_launcher_icons:
   android: "launcher_icon"