feat(studio): hide text panel for elements inside locked compositions

Elements inside a data-timeline-locked sub-composition now have the
TEXT property panel hidden. These elements are JS-generated — editing
them in the panel won't persist since the script rebuilds the DOM on
load. Uses findClosestByAttribute to detect the locked ancestor.

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

@@ -12,6 +12,7 @@ import type {
 } from "./domEditingTypes";
 import {
   buildStableSelector,
+  findClosestByAttribute,
   getCuratedComputedStyles,
   getDataAttributes,
   getInlineStyles,
@@ -318,6 +319,7 @@ export function resolveDomEditSelection(
       compositionPath,
       compositionSrc,
       isCompositionHost: Boolean(compositionSrc),
+      isInsideLockedComposition: Boolean(findClosestByAttribute(current, ["data-timeline-locked"])),
       label: buildElementLabel(current),
       tagName: current.tagName.toLowerCase(),
       boundingBox: {
@@ -488,7 +490,11 @@ export function getDomEditTargetKey(
 }
 
 export function isTextEditableSelection(selection: DomEditSelection): boolean {
-  return selection.textFields.length > 0 && !selection.isCompositionHost;
+  return (
+    selection.textFields.length > 0 &&
+    !selection.isCompositionHost &&
+    !selection.isInsideLockedComposition
+  );
 }
 
 // buildElementAgentPrompt is in domEditingAgentPrompt.ts

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

@@ -78,6 +78,7 @@ export interface DomEditSelection extends PatchTarget {
   compositionPath: string;
   compositionSrc?: string;
   isCompositionHost: boolean;
+  isInsideLockedComposition: boolean;
   boundingBox: { x: number; y: number; width: number; height: number };
   textContent: string | null;
   dataAttributes: Record<string, string>;