refactor: address review nits

- merge gsapResizeIntercept's duplicate module imports
- move the core-constant imports to the file headers (picker, domEditingDom)
- justify the cross-realm HTMLElement casts (iframe-realm nodes fail
  instanceof; access is duck-typed)

packages/studio/src/components/editor/domEditingDom.ts

@@ -3,6 +3,7 @@
  * selector utilities, and composition source resolution.
  * No imports from other domEditing* modules — safe to import from anywhere.
  */
+import { COLOR_GRADING_SOURCE_HIDDEN_ATTR } from "@hyperframes/core/color-grading";
 import { CURATED_STYLE_PROPERTIES } from "./domEditingTypes";
 
 // ─── Type guard ───────────────────────────────────────────────────────────────
@@ -28,8 +29,6 @@ export function isTextBearingTag(tagName: string): boolean {
   return ["div", "span", "p", "strong", "h1", "h2", "h3", "h4", "h5", "h6"].includes(tagName);
 }
 
-import { COLOR_GRADING_SOURCE_HIDDEN_ATTR } from "@hyperframes/core/color-grading";
-
 export function isElementVisibleThroughAncestors(el: HTMLElement): boolean {
   const win = el.ownerDocument.defaultView;
   if (!win) return true;