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/layer-mask-utils.ts

@@ -0,0 +1,18 @@
+import type { Layer } from "./layer";
+import type { LayerMask } from "./layer-mask";
+
+export function getLayerMask(layer: Layer | undefined): LayerMask | undefined {
+  if (layer.layerMask) return layer.layerMask;
+  if (!layer.clippingMask) return undefined;
+
+  return {
+    kind: "raster",
+    maskLayerId: layer.clippingMask.maskLayerId,
+    enabled: true,
+    inverted: false,
+  };
+}
+
+export function hasLayerMask(layer: Layer): boolean {
+  return Boolean(getLayerMask(layer));
+}