feat(ui): implement refreshed UX for Composer layout (#21212)

Co-authored-by: Keith Guerin <keithguerin@gmail.com>

packages/core/src/utils/events.ts

@@ -88,9 +88,12 @@ export interface HookPayload {
  * Payload for the 'hook-start' event.
  */
 export interface HookStartPayload extends HookPayload {
+  /**
+   * The source of the hook configuration.
+   */
+  source?: string;
   /**
    * The 1-based index of the current hook in the execution sequence.
-   * Used for progress indication (e.g. "Hook 1/3").
    */
   hookIndex?: number;
   /**