Add comprehensive KDoc documentation to FilterHelper (#54350)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/54350

Added comprehensive KDoc documentation to the FilterHelper object and its primary public method for parsing and applying CSS filter effects on Android S+ (API 31+).

changelog: [internal] internal

Reviewed By: lenaic

Differential Revision: D85926889

fbshipit-source-id: e20bb0697753e710d66acc3ef4078ab009d6dc5d

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/FilterHelper.kt

@@ -21,9 +21,25 @@ import com.facebook.react.uimanager.PixelUtil.dpToPx
 import kotlin.math.cos
 import kotlin.math.sin
 
+/**
+ * Helper object for parsing and applying CSS filter effects on Android S+ (API 31+).
+ *
+ * This object provides utilities to convert CSS filter arrays into Android [RenderEffect] chains
+ * and [ColorMatrixColorFilter] objects. Supports filters like blur, brightness, contrast,
+ * grayscale, sepia, saturate, hue-rotate, invert, opacity, and drop-shadow.
+ *
+ * @see <a href="https://www.w3.org/TR/filter-effects-1/">CSS Filter Effects Module Level 1</a>
+ */
 @TargetApi(31)
 internal object FilterHelper {
 
+  /**
+   * Parses a ReadableArray of CSS filter definitions into a chained [RenderEffect].
+   *
+   * @param filters The array of filter definitions, or null
+   * @return A chained RenderEffect representing all filters, or null if no filters provided
+   * @throws IllegalArgumentException if an invalid filter name is encountered
+   */
   @JvmStatic
   fun parseFilters(filters: ReadableArray?): RenderEffect? {
     filters ?: return null