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/asset-provenance.ts

@@ -0,0 +1,56 @@
+import type { Rect, Size } from "./geometry";
+import type { AssetId, LayerId } from "./id";
+
+export type GeneratedAssetMode = "text-to-image" | "image-to-image" | "inpaint" | "outpaint";
+
+export type GeneratedAssetAcceptance = "layer" | "variant-layer" | "replacement";
+
+export type AssetGenerationProvenance = {
+  kind: "generated";
+  candidateId: string;
+  mode: GeneratedAssetMode;
+  acceptance: GeneratedAssetAcceptance;
+  prompt: string;
+  negativePrompt: string;
+  seed: number;
+  outputSize: Size;
+  settings: {
+    architecture: string;
+    model: string;
+    textEncoder: string;
+    vae: string;
+    strength: number;
+    steps: number;
+    cfg: number;
+    sampler: string;
+    scheduler: string;
+    width: number;
+    height: number;
+  };
+  inpaint?: {
+    targetLayerId: LayerId;
+    maskLayerId: LayerId;
+    sourceAssetId: AssetId;
+    maskAssetId: AssetId;
+    crop: {
+      assetBounds: Rect;
+      documentBounds: Rect;
+      padding: number;
+      maskedAreaOnly: boolean;
+    };
+    mask: {
+      polarity: "hidden" | "revealed";
+      activeBounds: Rect;
+    };
+    backend: {
+      growMaskBy: number;
+      maskedContent: string;
+      maskBlur: number;
+      maskFeather: number;
+      maskExpand: number;
+      cropPadding: number;
+    };
+  };
+};
+
+export type AssetProvenance = AssetGenerationProvenance;