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

firebase_google_authentication/lib/Screens/HomePage.dart

@@ -6,7 +6,7 @@ import 'package:flutter_svg/flutter_svg.dart';
 import 'package:google_fonts/google_fonts.dart';
 
 class HomePage extends StatefulWidget {
-  const HomePage({Key? key}) : super(key: key);
+  const HomePage({super.key});
 
   @override
   _HomePageState createState() => _HomePageState();
@@ -62,7 +62,7 @@ class _HomePageState extends State<HomePage> {
         Row(
           mainAxisAlignment: MainAxisAlignment.center,
           children: [
-            Container(
+            SizedBox(
               width: size.width * 0.8,
               child: ClipRRect(
                 borderRadius: BorderRadius.circular(29),
@@ -92,7 +92,7 @@ class _HomePageState extends State<HomePage> {
         SizedBox(
           height: 15,
         ),
-        Container(
+        SizedBox(
           width: size.width * 0.8,
           child: ClipRRect(
             borderRadius: BorderRadius.circular(29),