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/ApplyFilters.dart

@@ -1,18 +1,18 @@
 import 'package:photofilters/photofilters.dart';
 import 'package:flutter/material.dart';
 import 'package:path/path.dart';
-import 'package:image/image.dart' as imageLib;
+import 'package:image/image.dart' as image_lib;
 
-ApplyFilters(context, _image) async {
-  var image = imageLib.decodeImage(_image.readAsBytesSync())!;
-  image = imageLib.copyResize(image, width: 600);
-  String fileName = basename(_image.path);
+Future<dynamic> ApplyFilters(context, image) async {
+  var decoded = image_lib.decodeImage(image.readAsBytesSync())!;
+  decoded = image_lib.copyResize(decoded, width: 600);
+  String fileName = basename(image.path);
   Map imagefile = await Navigator.push(
     context,
-    new MaterialPageRoute(
-      builder: (context) => new PhotoFilterSelector(
+    MaterialPageRoute(
+      builder: (context) => PhotoFilterSelector(
         title: Text("Photo Filter Example"),
-        image: image,
+        image: decoded,
         appBarColor: Colors.greenAccent[400]!,
         filters: presetFiltersList,
         filename: fileName,
@@ -21,9 +21,8 @@ ApplyFilters(context, _image) async {
       ),
     ),
   );
-  if (imagefile != null && imagefile.containsKey('image_filtered')) {
-    _image = imagefile['image_filtered'];
-    return _image;
+  if (imagefile.containsKey('image_filtered')) {
+    return imagefile['image_filtered'];
   } else {
     return null;
   }

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;
+  }
 }

image_editor/lib/GetImg.dart

@@ -1,11 +1,11 @@
 import 'package:image_picker/image_picker.dart';
 import 'dart:io';
 
-GetiImg(_image) async {
+Future<dynamic> GetiImg(image) async {
   var pickedFile = await ImagePicker().pickImage(source: ImageSource.gallery);
   if (pickedFile != null) {
-    _image = File(pickedFile.path);
-    return _image;
+    image = File(pickedFile.path);
+    return image;
   } else {
     return null;
   }

image_editor/lib/HomePage.dart

@@ -2,11 +2,12 @@ import 'package:flutter/material.dart';
 import 'package:image_editor/ApplyFilters.dart';
 import 'package:image_editor/EditImg.dart';
 import 'package:image_editor/GetImg.dart';
-import 'package:fluttertoast/fluttertoast.dart';
 import 'package:image_editor/SaveInGallery.dart';
 import 'dart:io';
 
 class HomePage extends StatefulWidget {
+  const HomePage({super.key});
+
   @override
   _HomePageState createState() => _HomePageState();
 }
@@ -15,7 +16,8 @@ class _HomePageState extends State<HomePage> {
   bool _selected = false; //to check if a image is selected or not
   late File
       _image; //here we will store the selected image and apply modifications
-  double _ImageContainerHeight = 450, _ImageContainerWidth = 400;
+  final double _ImageContainerHeight = 450;
+  final double _ImageContainerWidth = 400;
 
   @override
   Widget build(BuildContext context) {
@@ -27,7 +29,7 @@ class _HomePageState extends State<HomePage> {
       body: Container(
           child: Column(
         children: <Widget>[
-          Container(
+          SizedBox(
               height: _ImageContainerHeight,
               width: _ImageContainerWidth,
               child: _selected // checks if a image is selected or not
@@ -46,11 +48,11 @@ class _HomePageState extends State<HomePage> {
                     style: TextStyle(color: Colors.white),
                   ),
                   onPressed: () async {
-                    var _Ifile = await GetiImg(
+                    var Ifile = await GetiImg(
                         _image); // function called from GetImg.dart
-                    if (_Ifile != null) {
+                    if (Ifile != null) {
                       setState(() {
-                        _image = _Ifile;
+                        _image = Ifile;
                         _selected = true;
                       });
                     }
@@ -66,23 +68,12 @@ class _HomePageState extends State<HomePage> {
                     style: TextStyle(color: Colors.white),
                   ),
                   onPressed: () async {
-                    if (_image != null) {
-                      var _Ifile = await EditImg(
-                          _image); // function called from EditImg.dart
-                      if (_Ifile != null) {
-                        setState(() {
-                          _image = _Ifile;
-                        });
-                      }
-                    } else {
-                      Fluttertoast.showToast(
-                          msg: "Select a image first :-(",
-                          toastLength: Toast.LENGTH_SHORT,
-                          gravity: ToastGravity.BOTTOM,
-                          timeInSecForIosWeb: 1,
-                          backgroundColor: Colors.green,
-                          textColor: Colors.white,
-                          fontSize: 16.0);
+                    var Ifile0 = await EditImg(
+                        _image); // function called from EditImg.dart
+                    if (Ifile0 != null) {
+                      setState(() {
+                        _image = Ifile0;
+                      });
                     }
                   }),
               Spacer(
@@ -103,23 +94,12 @@ class _HomePageState extends State<HomePage> {
                     style: TextStyle(color: Colors.white),
                   ),
                   onPressed: () async {
-                    if (_image != null) {
-                      var _Ifile = await ApplyFilters(context,
-                          _image); // function called from ApplyFilters.dart
-                      if (_Ifile != null) {
-                        setState(() {
-                          _image = _Ifile;
-                        });
-                      }
-                    } else {
-                      Fluttertoast.showToast(
-                          msg: "Select a image first :-(",
-                          toastLength: Toast.LENGTH_SHORT,
-                          gravity: ToastGravity.BOTTOM,
-                          timeInSecForIosWeb: 1,
-                          backgroundColor: Colors.green,
-                          textColor: Colors.white,
-                          fontSize: 16.0);
+                    var Ifile0 = await ApplyFilters(context,
+                        _image); // function called from ApplyFilters.dart
+                    if (Ifile0 != null) {
+                      setState(() {
+                        _image = Ifile0;
+                      });
                     }
                   }),
               Spacer(
@@ -133,19 +113,8 @@ class _HomePageState extends State<HomePage> {
                     style: TextStyle(color: Colors.white),
                   ),
                   onPressed: () async {
-                    if (_image != null) {
-                      await SaveImg(
-                          _image); // function called from SaveInGallery.dart
-                    } else {
-                      Fluttertoast.showToast(
-                          msg: "Select a image first :-(",
-                          toastLength: Toast.LENGTH_SHORT,
-                          gravity: ToastGravity.BOTTOM,
-                          timeInSecForIosWeb: 1,
-                          backgroundColor: Colors.green,
-                          textColor: Colors.white,
-                          fontSize: 16.0);
-                    }
+                    await SaveImg(
+                        _image); // function called from SaveInGallery.dart
                   }),
               Spacer(
                 flex: 2,

image_editor/lib/SaveInGallery.dart

@@ -2,10 +2,9 @@ import 'package:flutter/material.dart';
 import 'package:gallery_saver_plus/gallery_saver.dart';
 import 'package:fluttertoast/fluttertoast.dart';
 
-SaveImg(_image) async {
-  var result =
-      await GallerySaver.saveImage(_image.path, albumName: 'ImageEditor')
-          .then((bool? success) {
+Future<void> SaveImg(image) async {
+  await GallerySaver.saveImage(image.path, albumName: 'ImageEditor')
+      .then((bool? success) {
     success == true
         ? Fluttertoast.showToast(
             msg: "Image saved in gallery/ImageEditor",

image_editor/lib/main.dart

@@ -6,6 +6,8 @@ void main() {
 }
 
 class MyApp extends StatelessWidget {
+  const MyApp({super.key});
+
   // This widget is the root of your application.
   @override
   Widget build(BuildContext context) {