refactor: standardize Dart and Android config across all 54 apps

- Bump all apps to sdk >=3.0.0 <4.0.0 and add flutter_lints + a shared
  analysis_options.yaml to every app (flutter analyze is now green repo-wide)
- Fix real compile errors in firebase_google_authentication and image_editor,
  plus deprecated APIs (Matrix4, SvgPicture.color, textScaleFactor),
  missing async 'mounted' guards, and misc lints via dart fix + manual fixes
- Align pubspec 'name' with each folder and Android namespace/applicationId
  with the documented github.nisrulz.* convention
- Convert bmi_calculator from a legacy Flutter module to a standard app
  with a proper android/ scaffold; fix missing android:exported in launcher
  manifests across 22 apps so all Android builds pass
- Untrack generated build files (GeneratedPluginRegistrant,
  .flutter-plugins-dependencies) and ignore them

using_listview/lib/contactlist/contact_list.dart

@@ -5,7 +5,7 @@ import 'package:using_listview/contactlist/modal/contact.dart';
 class ContactsList extends StatelessWidget {
   final List<ContactModal> _contactModal;
 
-  ContactsList(this._contactModal);
+  const ContactsList(this._contactModal, {super.key});
 
   @override
   Widget build(BuildContext context) {

using_listview/lib/contactlist/contact_list_item.dart

@@ -4,7 +4,7 @@ import 'package:using_listview/contactlist/modal/contact.dart';
 class ContactListItem extends StatelessWidget {
   final ContactModal _contactModal;
 
-  ContactListItem(this._contactModal);
+  const ContactListItem(this._contactModal, {super.key});
 
   @override
   Widget build(BuildContext context) {