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

bmi_calculator/.metadata

@@ -4,7 +4,27 @@
 # This file should be version controlled and should not be manually edited.
 
 version:
-  revision: f1875d570e39de09040c8f79aa13cc56baab8db1
-  channel: stable
+  revision: "4cf24164269a5ebf0c16a028a00727d0e77bbb05"
+  channel: "stable"
 
-project_type: module
+project_type: app
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: 4cf24164269a5ebf0c16a028a00727d0e77bbb05
+      base_revision: 4cf24164269a5ebf0c16a028a00727d0e77bbb05
+    - platform: android
+      create_revision: 4cf24164269a5ebf0c16a028a00727d0e77bbb05
+      base_revision: 4cf24164269a5ebf0c16a028a00727d0e77bbb05
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'