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.

core/base-layer.ts

@@ -1,5 +1,6 @@
 import type { Transform } from "./geometry";
 import type { LayerId } from "./id";
+import type { LayerMask } from "./layer-mask";
 
 export type LayerClippingMask = {
   maskLayerId: LayerId;
@@ -12,5 +13,7 @@ export type BaseLayer = {
   locked: boolean;
   opacity: number;
   transform: Transform;
+  layerMask?: LayerMask;
+  /** @deprecated Use layerMask. Kept readable for older documents. */
   clippingMask?: LayerClippingMask;
 };