feat: enhance layer mask handling and opacity management

- Introduced `getLayerMask` utility to streamline layer mask retrieval.
- Updated layer rendering logic to incorporate layer masks and opacity adjustments.
- Added functionality to prevent dropping a group into its descendants.
- Enhanced image texture rendering to support opacity parameters across various rendering functions.
- Implemented group layer bounds application for better scaling and positioning.
- Added tests to ensure correct behavior when handling layer masks and group layers.
- Created new types for asset generation provenance to track generated assets more effectively.

editor/document-indexes.ts

@@ -3,6 +3,7 @@ import type { ImageDocument } from "@core/document";
 import type { Rect } from "@core/geometry";
 import type { ArtboardId, AssetId, LayerId } from "@core/id";
 import type { Layer } from "@core/layer";
+import { getLayerMask } from "@core/layer-mask-utils";
 
 export type IndexedLayerInfo = {
   artboardId: ArtboardId;
@@ -113,9 +114,10 @@ function indexLayerTree(options: {
       index,
     });
 
-    if (layer.clippingMask) {
-      options.documentMaskLayerIds.add(layer.clippingMask.maskLayerId);
-      layerListMaskLayerIds.add(layer.clippingMask.maskLayerId);
+    const layerMask = getLayerMask(layer);
+    if (layerMask) {
+      options.documentMaskLayerIds.add(layerMask.maskLayerId);
+      layerListMaskLayerIds.add(layerMask.maskLayerId);
     }
 
     if (layer.type === "group") {