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

expense_planner/lib/widgets/transaction_list.dart

@@ -7,11 +7,11 @@ class TransactionList extends StatelessWidget {
   final List<Transaction> transactions;
   final Function deleteTx;
 
-  TransactionList(this.transactions, this.deleteTx);
+  const TransactionList(this.transactions, this.deleteTx, {super.key});
 
   @override
   Widget build(BuildContext context) {
-    return Container(
+    return SizedBox(
       height: 450,
       child: transactions.isEmpty
           ? Column(
@@ -23,7 +23,7 @@ class TransactionList extends StatelessWidget {
                 SizedBox(
                   height: 20,
                 ),
-                Container(
+                SizedBox(
                     height: 200,
                     child: Image.asset(
                       'assets/images/waiting.png',