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

load_local_json/analysis_options.yaml

@@ -0,0 +1,23 @@
+# Lint rules for Flutter apps.
+# See https://dart.dev/guides/language/analysis-options
+include: package:flutter_lints/flutter.yaml
+
+analyzer:
+  exclude:
+    - build/**
+    - android/**
+    - ios/**
+    - web/**
+    - windows/**
+    - macos/**
+    - linux/**
+
+linter:
+  rules:
+    # Noise in small sample apps; keep the code readable.
+    avoid_print: false
+    avoid_unnecessary_containers: false
+    file_names: false
+    library_private_types_in_public_api: false
+    non_constant_identifier_names: false
+    strict_top_level_inference: false

load_local_json/lib/main.dart

@@ -9,6 +9,8 @@ void main() {
 }
 
 class MyApp extends StatefulWidget {
+  const MyApp({super.key});
+
   @override
   MyAppState createState() => MyAppState();
 }
@@ -30,7 +32,7 @@ class MyAppState extends State<MyApp> {
                     .loadString('data_repo/starwars_data.json'),
                 builder: (context, snapshot) {
                   // Decode the JSON
-                  var new_data = json.decode(snapshot.data.toString());
+                  var newData = json.decode(snapshot.data.toString());
 
                   return ListView.builder(
                     // Build the ListView
@@ -39,22 +41,19 @@ class MyAppState extends State<MyApp> {
                         child: Column(
                           crossAxisAlignment: CrossAxisAlignment.stretch,
                           children: <Widget>[
-                            Text("Name: " + new_data[index]['name']),
-                            Text("Height: " + new_data[index]['height']),
-                            Text("Mass: " + new_data[index]['mass']),
-                            Text(
-                                "Hair Color: " + new_data[index]['hair_color']),
-                            Text(
-                                "Skin Color: " + new_data[index]['skin_color']),
-                            Text("Eye Color: " + new_data[index]['eye_color']),
-                            Text(
-                                "Birth Year: " + new_data[index]['birth_year']),
-                            Text("Gender: " + new_data[index]['gender'])
+                            Text("Name: ${newData[index]['name']}"),
+                            Text("Height: ${newData[index]['height']}"),
+                            Text("Mass: ${newData[index]['mass']}"),
+                            Text("Hair Color: ${newData[index]['hair_color']}"),
+                            Text("Skin Color: ${newData[index]['skin_color']}"),
+                            Text("Eye Color: ${newData[index]['eye_color']}"),
+                            Text("Birth Year: ${newData[index]['birth_year']}"),
+                            Text("Gender: ${newData[index]['gender']}")
                           ],
                         ),
                       );
                     },
-                    itemCount: new_data == null ? 0 : new_data.length,
+                    itemCount: newData == null ? 0 : newData.length,
                   );
                 }),
           ),

load_local_json/pubspec.yaml

@@ -11,6 +11,7 @@ dependencies:
 dev_dependencies:
   flutter_test:
     sdk: flutter
+  flutter_lints: ^6.0.0
 
 
 # For information on the generic Dart part of this file, see the