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

image_editor/lib/EditImg.dart

@@ -1,9 +1,9 @@
 import 'package:flutter/material.dart';
 import 'package:image_cropper/image_cropper.dart';
 
-EditImg(_image) async {
+Future<dynamic> EditImg(image) async {
   var CroppedImg =
-      await ImageCropper().cropImage(sourcePath: _image.path, uiSettings: [
+      await ImageCropper().cropImage(sourcePath: image.path, uiSettings: [
     AndroidUiSettings(
         toolbarTitle: 'Cropper',
         toolbarColor: Colors.greenAccent[400],
@@ -15,8 +15,9 @@ EditImg(_image) async {
     ),
   ]);
   if (CroppedImg != null) {
-    _image = CroppedImg;
-    return _image;
-  } else
+    image = CroppedImg;
+    return image;
+  } else {
     return null;
+  }
 }