Add selection to TextInput onChange event

Summary:
This change adds `selection` data to the `TextInput.onChange` event for both iOS and Android platforms.

## Why

On the web, text input elements provide `selectionStart` and `selectionEnd` properties that are always accessible during input events. This is a W3C DOM standard that enables common use cases like:

- mention and tagging systems (insert at cursor position)
- Autocomplete/typeahead (replace text at cursor)
- Input masking (format text while maintaining cursor position)
- Rich text editing features

React Native's `onChange` event previously included `selection` on iOS (Fabric), but this was removed in D76253999 to unify with Android (which never had it). This change restores and extends this capability to both platforms, better aligning React Native with web standards.

## What Changed

1. **Flow Types**: Added optional `selection?: Selection` to `TextInputChangeEventData`
2. **iOS/macOS (C++)**: Enable selection in `onChange` event via `TextInputEventEmitter`
3. **Android (Kotlin)**: Added selection data to `ReactTextChangedEvent`
4. **RNTester**: Updated examples to verify the change

## Changelog

[General][Added] - TextInput onChange event now includes selection data on iOS and Android

Differential Revision: D89898092

Author: alanleedev

packages/react-native/Libraries/Components/TextInput/TextInput.flow.js

@@ -29,6 +29,7 @@ type TextInputChangeEventData = $ReadOnly<{
   eventCount: number,
   target: number,
   text: string,
+  selection?: Selection,
 }>;
 
 export type TextInputChangeEvent =

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactTextChangedEvent.kt

@@ -17,6 +17,8 @@ internal class ReactTextChangedEvent(
     viewId: Int,
     private val text: String,
     private val eventCount: Int,
+    private val selectionStart: Int,
+    private val selectionEnd: Int,
 ) : Event<ReactTextChangedEvent>(surfaceId, viewId) {
   override fun getEventName(): String = EVENT_NAME
 
@@ -25,6 +27,12 @@ internal class ReactTextChangedEvent(
       putString("text", text)
       putInt("eventCount", eventCount)
       putInt("target", viewTag)
+      val selectionData =
+          Arguments.createMap().apply {
+            putInt("start", selectionStart)
+            putInt("end", selectionEnd)
+          }
+      putMap("selection", selectionData)
     }
   }
 

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactTextInputTextWatcher.kt

@@ -63,6 +63,8 @@ internal class ReactTextInputTextWatcher(
             editText.id,
             s.toString(),
             editText.incrementAndGetEventCounter(),
+            editText.selectionStart,
+            editText.selectionEnd,
         )
     )
   }

packages/react-native/ReactCommon/react/renderer/components/textinput/TextInputEventEmitter.cpp

@@ -140,7 +140,7 @@ void TextInputEventEmitter::onBlur(const Metrics& textInputMetrics) const {
 }
 
 void TextInputEventEmitter::onChange(const Metrics& textInputMetrics) const {
-  dispatchTextInputEvent("change", textInputMetrics);
+  dispatchTextInputEvent("change", textInputMetrics, true);
 }
 
 void TextInputEventEmitter::onContentSizeChange(

packages/react-native/ReactNativeApi.d.ts

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<bffba0612c645ddb6166e1f5bb1187f2>>
+ * @generated SignedSource<<249ca589a73aaef41a965bcf3a2c0208>>
  *
  * This file was generated by scripts/js-api/build-types/index.js.
  */
@@ -5277,6 +5277,7 @@ declare type TextInputChangeEvent =
   NativeSyntheticEvent<TextInputChangeEventData>
 declare type TextInputChangeEventData = {
   readonly eventCount: number
+  readonly selection?: Selection
   readonly target: number
   readonly text: string
 }
@@ -6189,15 +6190,15 @@ export {
   TaskProvider, // 266dedf2
   Text, // e55ac2e2
   TextContentType, // 239b3ecc
-  TextInput, // cf7a3331
+  TextInput, // 2e89b91d
   TextInputAndroidProps, // 3f09ce49
-  TextInputChangeEvent, // 380cbe93
+  TextInputChangeEvent, // 6821f629
   TextInputContentSizeChangeEvent, // 5fba3f54
   TextInputEndEditingEvent, // 8c22fac3
   TextInputFocusEvent, // c36e977c
   TextInputIOSProps, // 0d05a855
   TextInputKeyPressEvent, // 967178c2
-  TextInputProps, // a817a7f7
+  TextInputProps, // c75f0362
   TextInputSelectionChangeEvent, // a1a7622f
   TextInputSubmitEditingEvent, // 48d903af
   TextLayoutEvent, // 45b0a8d7

packages/rn-tester/js/examples/TextInput/TextInputSharedExamples.js

@@ -393,7 +393,14 @@ class TextEventsExample extends React.Component<{...}, $FlowFixMe> {
           onFocus={() => this.updateText('onFocus')}
           onBlur={() => this.updateText('onBlur')}
           onChange={event =>
-            this.updateText('onChange text: ' + event.nativeEvent.text)
+            this.updateText(
+              'onChange text: ' +
+                event.nativeEvent.text +
+                ', selection: ' +
+                (event.nativeEvent.selection != null
+                  ? JSON.stringify(event.nativeEvent.selection)
+                  : 'undefined'),
+            )
           }
           onContentSizeChange={event =>
             this.updateText(