pub.dev score: license, dartdoc, analysis, tests

- Add MIT license
- Add dartdoc to all public APIs (UxKeyboard, BendBox, Bezier, Json)
- Add analysis_options.yaml with flutter_lints and public_member_api_docs
- Add repository, issue_tracker, topics to pubspec.yaml
- Expand package description
- Fix BendBox constructor (const, super.key)
- Remove unused import in keyboard.dart
- Replace boilerplate tests with UxKeyboard smoke tests
- Move ux dependency to example's dependencies (not dev_dependencies)

example/pubspec.yaml

@@ -8,56 +8,14 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
-
-  # The following adds the Cupertino Icons font to your application.
-  # Use with the CupertinoIcons class for iOS style icons.
   cupertino_icons: 1.0.8
-
-dev_dependencies:
-  flutter_test:
-    sdk: flutter
-
   ux:
     path: ../
 
-# For information on the generic Dart part of this file, see the
-# following page: https://dart.dev/tools/pub/pubspec
+dev_dependencies:
+  flutter_lints: ^6.0.0
+  flutter_test:
+    sdk: flutter
 
-# The following section is specific to Flutter.
 flutter:
-
-  # The following line ensures that the Material Icons font is
-  # included with your application, so that you can use the icons in
-  # the material Icons class.
   uses-material-design: true
-
-  # To add assets to your application, add an assets section, like this:
-  # assets:
-  #  - images/a_dot_burr.jpeg
-  #  - images/a_dot_ham.jpeg
-
-  # An image asset can refer to one or more resolution-specific "variants", see
-  # https://flutter.dev/assets-and-images/#resolution-aware.
-
-  # For details regarding adding assets from package dependencies, see
-  # https://flutter.dev/assets-and-images/#from-packages
-
-  # To add custom fonts to your application, add a fonts section here,
-  # in this "flutter" section. Each entry in this list should have a
-  # "family" key with the font family name, and a "fonts" key with a
-  # list giving the asset and other descriptors for the font. For
-  # example:
-  # fonts:
-  #   - family: Schyler
-  #     fonts:
-  #       - asset: fonts/Schyler-Regular.ttf
-  #       - asset: fonts/Schyler-Italic.ttf
-  #         style: italic
-  #   - family: Trajan Pro
-  #     fonts:
-  #       - asset: fonts/TrajanPro.ttf
-  #       - asset: fonts/TrajanPro_Bold.ttf
-  #         weight: 700
-  #
-  # For details regarding fonts from package dependencies,
-  # see https://flutter.dev/custom-fonts/#from-packages