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

using_listwheelscrollview/ios/Runner/GeneratedPluginRegistrant.h

@@ -1,19 +0,0 @@
-//
-//  Generated file. Do not edit.
-//
-
-// clang-format off
-
-#ifndef GeneratedPluginRegistrant_h
-#define GeneratedPluginRegistrant_h
-
-#import <Flutter/Flutter.h>
-
-NS_ASSUME_NONNULL_BEGIN
-
-@interface GeneratedPluginRegistrant : NSObject
-+ (void)registerWithRegistry:(NSObject<FlutterPluginRegistry>*)registry;
-@end
-
-NS_ASSUME_NONNULL_END
-#endif /* GeneratedPluginRegistrant_h */

using_listwheelscrollview/ios/Runner/GeneratedPluginRegistrant.m

@@ -1,14 +0,0 @@
-//
-//  Generated file. Do not edit.
-//
-
-// clang-format off
-
-#import "GeneratedPluginRegistrant.h"
-
-@implementation GeneratedPluginRegistrant
-
-+ (void)registerWithRegistry:(NSObject<FlutterPluginRegistry>*)registry {
-}
-
-@end