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/test/widget_test.dart

@@ -1,26 +1,11 @@
-// This is a basic Flutter widget test.
-//
-// To perform an interaction with a widget in your test, use the WidgetTester
-// utility that Flutter provides. For example, you can send tap and scroll
-// gestures. You can also use WidgetTester to find child widgets in the widget
-// tree, read text, and verify that the values of widget properties are correct.
-
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:ux_example/main.dart';
 
 void main() {
-  testWidgets('Verify Platform version', (WidgetTester tester) async {
-    // Build our app and trigger a frame.
-    await tester.pumpWidget(MyApp());
-
-    // Verify that platform version is retrieved.
-    expect(
-      find.byWidgetPredicate(
-        (Widget widget) =>
-            widget is Text && (widget.data?.startsWith('Running on:') ?? false),
-      ),
-      findsOneWidget,
-    );
+  testWidgets('ChatScreen renders', (WidgetTester tester) async {
+    await tester.pumpWidget(MaterialApp(home: ChatScreen()));
+    expect(find.text('UxKeyboard Chat'), findsOneWidget);
+    expect(find.text('Type a message...'), findsOneWidget);
   });
 }