Describe the pre-mount before the traversal in the flag's description

The description named only the slices after each frame. A frame that
follows one whose draw slept also pre-mounts before its traversal, so the
description now says so, as PreMountItemsBetweenFrames does.

Author: YevheniiKotyrlo

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlags.kt

@@ -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<<abb5d24dad0e0685eea26d5b8d0e035f>>
+ * @generated SignedSource<<6d17652dc2d02644c8b5ad0133d2dae3>>
  */
 
 /**
@@ -313,7 +313,7 @@ public object ReactNativeFeatureFlags {
   public fun enablePreallocatedPropsDiffOnInsertAndroid(): Boolean = accessor.enablePreallocatedPropsDiffOnInsertAndroid()
 
   /**
-   * Pre-mount views on Android after each frame is drawn, in short slices that stop before the next vsync, instead of before the frame is drawn for half of a 60 Hz frame.
+   * Pre-mount views on Android in the time each frame leaves free: after the frame, in short slices that stop before the next vsync, and before its traversal for as long as the previous draw slept, at most half a frame, instead of before every traversal for half of a 60 Hz frame.
    */
   @JvmStatic
   public fun enablePremountItemsBetweenFramesAndroid(): Boolean = accessor.enablePremountItemsBetweenFramesAndroid()

packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlags.h

@@ -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<<35accad3c60bf332b67e61529aab9d61>>
+ * @generated SignedSource<<6ffd411c79e6502fee182c3e54e9eb0a>>
  */
 
 /**
@@ -277,7 +277,7 @@ class ReactNativeFeatureFlags {
   RN_EXPORT static bool enablePreallocatedPropsDiffOnInsertAndroid();
 
   /**
-   * Pre-mount views on Android after each frame is drawn, in short slices that stop before the next vsync, instead of before the frame is drawn for half of a 60 Hz frame.
+   * Pre-mount views on Android in the time each frame leaves free: after the frame, in short slices that stop before the next vsync, and before its traversal for as long as the previous draw slept, at most half a frame, instead of before every traversal for half of a 60 Hz frame.
    */
   RN_EXPORT static bool enablePremountItemsBetweenFramesAndroid();
 

packages/react-native/scripts/featureflags/ReactNativeFeatureFlags.config.js

@@ -560,7 +560,7 @@ const definitions: FeatureFlagDefinitions = {
       metadata: {
         dateAdded: '2026-10-20',
         description:
-          'Pre-mount views on Android after each frame is drawn, in short slices that stop before the next vsync, instead of before the frame is drawn for half of a 60 Hz frame.',
+          'Pre-mount views on Android in the time each frame leaves free: after the frame, in short slices that stop before the next vsync, and before its traversal for as long as the previous draw slept, at most half a frame, instead of before every traversal for half of a 60 Hz frame.',
         expectedReleaseValue: true,
         purpose: 'experimentation',
       },

packages/react-native/src/private/featureflags/ReactNativeFeatureFlags.js

@@ -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<<6ea3d949b27ee02705ec859642be72ab>>
+ * @generated SignedSource<<3f253bd16eaaf577089194b4442ec2c6>>
  * @flow strict
  * @noformat
  */
@@ -409,7 +409,7 @@ export const enableNativeCSSParsing: Getter<boolean> = createNativeFlagGetter('e
  */
 export const enablePreallocatedPropsDiffOnInsertAndroid: Getter<boolean> = createNativeFlagGetter('enablePreallocatedPropsDiffOnInsertAndroid', false);
 /**
- * Pre-mount views on Android after each frame is drawn, in short slices that stop before the next vsync, instead of before the frame is drawn for half of a 60 Hz frame.
+ * Pre-mount views on Android in the time each frame leaves free: after the frame, in short slices that stop before the next vsync, and before its traversal for as long as the previous draw slept, at most half a frame, instead of before every traversal for half of a 60 Hz frame.
  */
 export const enablePremountItemsBetweenFramesAndroid: Getter<boolean> = createNativeFlagGetter('enablePremountItemsBetweenFramesAndroid', false);
 /**