Convert ReactScrollView and ReactNestedScrollView to Kotlin

Summary:
Convert `ReactScrollView.java` to `ReactScrollView.kt` and update the `generate-nested-scroll-view.js` script to generate `ReactNestedScrollView.kt` from the Kotlin source.

Key changes:
- `ReactScrollView.java` replaced by idiomatic `ReactScrollView.kt`
- `ReactNestedScrollView.java` replaced by generated `ReactNestedScrollView.kt`
- Generation script updated for Kotlin source/output file paths and transformations
- BUCK file updated to reference `.kt` files in the verification genrule
- `ReactScrollViewManager.kt` updated to use Kotlin property access syntax for `scrollEnabled`, `stateWrapper`, and `fadingEdgeLengthStart/End`
- Public API surface preserved: only additive `synthetic` constructor from `JvmOverloads`

Changelog:
[Android][Changed] - Convert `ReactScrollView` and `ReactNestedScrollView` from Java to Kotlin

Differential Revision: D107236882

Author: cortinico

packages/react-native/ReactAndroid/api/ReactAndroid.api

@@ -5429,6 +5429,30 @@ public abstract interface class com/facebook/react/views/scroll/FpsListener {
 	public abstract fun isEnabled ()Z
 }
 
+public final class com/facebook/react/views/scroll/MaintainVisibleScrollPositionHelper : com/facebook/react/bridge/UIManagerListener {
+	public fun <init> (Landroid/view/ViewGroup;Z)V
+	public fun didDispatchMountItems (Lcom/facebook/react/bridge/UIManager;)V
+	public fun didMountItems (Lcom/facebook/react/bridge/UIManager;)V
+	public fun didScheduleMountItems (Lcom/facebook/react/bridge/UIManager;)V
+	public final fun getConfig ()Lcom/facebook/react/views/scroll/MaintainVisibleScrollPositionHelper$Config;
+	public final fun setConfig (Lcom/facebook/react/views/scroll/MaintainVisibleScrollPositionHelper$Config;)V
+	public final fun start ()V
+	public final fun stop ()V
+	public fun willDispatchViewUpdates (Lcom/facebook/react/bridge/UIManager;)V
+	public fun willMountItems (Lcom/facebook/react/bridge/UIManager;)V
+}
+
+public final class com/facebook/react/views/scroll/MaintainVisibleScrollPositionHelper$Config {
+	public static final field Companion Lcom/facebook/react/views/scroll/MaintainVisibleScrollPositionHelper$Config$Companion;
+	public static final fun fromReadableMap (Lcom/facebook/react/bridge/ReadableMap;)Lcom/facebook/react/views/scroll/MaintainVisibleScrollPositionHelper$Config;
+	public final fun getAutoScrollToTopThreshold ()Ljava/lang/Integer;
+	public final fun getMinIndexForVisible ()I
+}
+
+public final class com/facebook/react/views/scroll/MaintainVisibleScrollPositionHelper$Config$Companion {
+	public final fun fromReadableMap (Lcom/facebook/react/bridge/ReadableMap;)Lcom/facebook/react/views/scroll/MaintainVisibleScrollPositionHelper$Config;
+}
+
 public final class com/facebook/react/views/scroll/OnScrollDispatchHelper {
 	public fun <init> ()V
 	public final fun getXFlingVelocity ()F
@@ -5598,6 +5622,7 @@ public final class com/facebook/react/views/scroll/ReactHorizontalScrollViewMana
 public class com/facebook/react/views/scroll/ReactScrollView : android/widget/ScrollView, android/view/View$OnLayoutChangeListener, android/view/ViewGroup$OnHierarchyChangeListener, com/facebook/react/uimanager/ReactClippingViewGroup, com/facebook/react/uimanager/ReactOverflowViewWithInset, com/facebook/react/views/scroll/ReactAccessibleScrollView, com/facebook/react/views/scroll/ReactScrollViewHelper$HasFlingAnimator, com/facebook/react/views/scroll/ReactScrollViewHelper$HasScrollEventThrottle, com/facebook/react/views/scroll/ReactScrollViewHelper$HasScrollState, com/facebook/react/views/scroll/ReactScrollViewHelper$HasSmoothScroll, com/facebook/react/views/scroll/ReactScrollViewHelper$HasStateWrapper, com/facebook/react/views/scroll/VirtualViewContainer {
 	public fun <init> (Landroid/content/Context;)V
 	public fun <init> (Landroid/content/Context;Lcom/facebook/react/views/scroll/FpsListener;)V
+	public synthetic fun <init> (Landroid/content/Context;Lcom/facebook/react/views/scroll/FpsListener;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public fun abortAnimation ()V
 	public fun dispatchGenericMotionEvent (Landroid/view/MotionEvent;)Z
 	public fun draw (Landroid/graphics/Canvas;)V
@@ -5925,6 +5950,28 @@ public abstract interface class com/facebook/react/views/scroll/VirtualView {
 	public abstract fun onModeChange (Lcom/facebook/react/views/virtual/VirtualViewMode;Landroid/graphics/Rect;)V
 }
 
+public abstract class com/facebook/react/views/scroll/VirtualViewContainerState {
+	public static final field Companion Lcom/facebook/react/views/scroll/VirtualViewContainerState$Companion;
+	public fun <init> (Landroid/view/ViewGroup;)V
+	public static final fun create (Landroid/view/ViewGroup;)Lcom/facebook/react/views/scroll/VirtualViewContainerState;
+	protected final fun getEmptyRect ()Landroid/graphics/Rect;
+	protected final fun getPrerenderRatio ()D
+	protected final fun getPrerenderRect ()Landroid/graphics/Rect;
+	protected final fun getScrollView ()Landroid/view/ViewGroup;
+	protected abstract fun getVirtualViews ()Ljava/util/Collection;
+	protected final fun getVisibleRect ()Landroid/graphics/Rect;
+	public fun onChange (Lcom/facebook/react/views/scroll/VirtualView;)V
+	public fun remove (Lcom/facebook/react/views/scroll/VirtualView;)V
+	protected abstract fun updateModes (Lcom/facebook/react/views/scroll/VirtualView;)V
+	public static synthetic fun updateModes$default (Lcom/facebook/react/views/scroll/VirtualViewContainerState;Lcom/facebook/react/views/scroll/VirtualView;ILjava/lang/Object;)V
+	protected final fun updateRects ()V
+	public final fun updateState ()V
+}
+
+public final class com/facebook/react/views/scroll/VirtualViewContainerState$Companion {
+	public final fun create (Landroid/view/ViewGroup;)Lcom/facebook/react/views/scroll/VirtualViewContainerState;
+}
+
 public class com/facebook/react/views/swiperefresh/ReactSwipeRefreshLayout : androidx/swiperefreshlayout/widget/SwipeRefreshLayout {
 	public fun <init> (Lcom/facebook/react/bridge/ReactContext;)V
 	public fun canChildScrollUp ()Z

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/scroll/MaintainVisibleScrollPositionHelper.kt

@@ -28,12 +28,12 @@ import java.lang.ref.WeakReference
  * This uses UIManager to listen to updates and capture position of items before and after layout.
  */
 @OptIn(UnstableReactNativeAPI::class)
-internal class MaintainVisibleScrollPositionHelper<ScrollViewT>(
+public class MaintainVisibleScrollPositionHelper<ScrollViewT>(
     private val scrollView: ScrollViewT,
     private val horizontal: Boolean,
 ) : UIManagerListener where ScrollViewT : HasSmoothScroll?, ScrollViewT : ViewGroup? {
 
-  var config: Config? = null
+  public var config: Config? = null
   private var firstVisibleViewRef: WeakReference<View>? = null
   private var prevFirstVisibleFrame: Rect? = null
   private var isListening = false
@@ -50,11 +50,14 @@ internal class MaintainVisibleScrollPositionHelper<ScrollViewT>(
             )
         )
 
-  class Config
-  internal constructor(val minIndexForVisible: Int, val autoScrollToTopThreshold: Int?) {
-    companion object {
+  public class Config
+  internal constructor(
+      public val minIndexForVisible: Int,
+      public val autoScrollToTopThreshold: Int?,
+  ) {
+    public companion object {
       @JvmStatic
-      fun fromReadableMap(value: ReadableMap): Config {
+      public fun fromReadableMap(value: ReadableMap): Config {
         val minIndexForVisible = value.getInt("minIndexForVisible")
         val autoScrollToTopThreshold =
             if (value.hasKey("autoscrollToTopThreshold")) value.getInt("autoscrollToTopThreshold")
@@ -65,7 +68,7 @@ internal class MaintainVisibleScrollPositionHelper<ScrollViewT>(
   }
 
   /** Start listening to view hierarchy updates. Should be called when this is created. */
-  fun start() {
+  public fun start() {
     if (isListening) {
       return
     }
@@ -74,7 +77,7 @@ internal class MaintainVisibleScrollPositionHelper<ScrollViewT>(
   }
 
   /** Stop listening to view hierarchy updates. Should be called before this is destroyed. */
-  fun stop() {
+  public fun stop() {
     if (!isListening) {
       return
     }