feat: implement inpainting functionality with mask handling

- Added `createMaskedPixelReplacementSource` function to handle pixel replacement using inpainting.
- Introduced `buildInpaintBundle` to prepare inpainting data including mask generation and validation.
- Created utility functions for mask operations such as `applyMaskedContentModeToRgba`, `expandRectWithinBounds`, and others for mask manipulation.
- Developed tests for inpainting preparation and mask raster utilities to ensure functionality and correctness.
- Implemented mask raster operations including inversion, feathering, blurring, and more.

renderer/renderer.ts

@@ -4,7 +4,7 @@ import { renderArtboard } from "./artboard";
 import { createBrushPreviewRenderer } from "./brush-preview";
 import { createCheckerboardRenderer } from "./checkerboard";
 import { createImageTextureRenderer } from "./image-textures";
-import { renderLayers } from "./layers";
+import { generationCandidatePreviewAssets, renderLayers } from "./layers";
 import { renderSelectionOverlay } from "./selection";
 import { renderTransformControls } from "./transform-controls";
 import type { WebGlRendererContext } from "./types";
@@ -62,7 +62,7 @@ export function createRenderer(canvas: HTMLCanvasElement, backend: RendererBacke
       for (const artboard of frame.document.artboards) {
         if (artboard.visible) renderArtboard(rendererContext, artboard, frame.editor.viewport, checkerboardRenderer);
       }
-      imageTextureRenderer.syncAssets(frame.document.assets);
+      imageTextureRenderer.syncAssets([...frame.document.assets, ...generationCandidatePreviewAssets(frame.editor)]);
       renderLayers(rendererContext, frame.document, frame.editor, imageTextureRenderer);
 
       if (!frame.editor.maskEdit) {