feat(studio): disable move/resize/style editing for locked composition children

Elements inside a data-timeline-locked composition now have all
canvas interactions disabled (move, resize, manual offset/size/rotation,
style editing). Prevents "Unable to patch" errors when trying to move
JS-generated caption elements that can't be patched back to source.

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

@@ -176,18 +176,21 @@ export function resolveDomEditCapabilities(args: {
   inlineStyles: Record<string, string>;
   computedStyles: Record<string, string>;
   isCompositionHost: boolean;
+  isInsideLockedComposition: boolean;
   isMasterView: boolean;
 }): DomEditCapabilities {
-  if (!args.selector) {
+  if (!args.selector || args.isInsideLockedComposition) {
     return {
-      canSelect: false,
+      canSelect: !args.isInsideLockedComposition,
       canEditStyles: false,
       canMove: false,
       canResize: false,
       canApplyManualOffset: false,
       canApplyManualSize: false,
       canApplyManualRotation: false,
-      reasonIfDisabled: "Studio could not resolve a stable patch target for this element.",
+      reasonIfDisabled: args.isInsideLockedComposition
+        ? "This element belongs to a locked composition."
+        : "Studio could not resolve a stable patch target for this element.",
     };
   }
 
@@ -299,6 +302,7 @@ export function resolveDomEditSelection(
     const inlineStyles = getInlineStyles(current);
     const computedStyles = getCuratedComputedStyles(current);
     const textFields = collectDomEditTextFields(current);
+    const isInsideLocked = Boolean(findClosestByAttribute(current, ["data-timeline-locked"]));
     const capabilities = resolveDomEditCapabilities({
       selector,
       tagName: current.tagName.toLowerCase(),
@@ -306,6 +310,7 @@ export function resolveDomEditSelection(
       inlineStyles,
       computedStyles,
       isCompositionHost: Boolean(compositionSrc),
+      isInsideLockedComposition: isInsideLocked,
       isMasterView: options.isMasterView,
     });
     const rect = current.getBoundingClientRect();
@@ -319,7 +324,7 @@ export function resolveDomEditSelection(
       compositionPath,
       compositionSrc,
       isCompositionHost: Boolean(compositionSrc),
-      isInsideLockedComposition: Boolean(findClosestByAttribute(current, ["data-timeline-locked"])),
+      isInsideLockedComposition: isInsideLocked,
       label: buildElementLabel(current),
       tagName: current.tagName.toLowerCase(),
       boundingBox: {