feat: add inpaint region functionality and related tools

- Enhanced cursor behavior for new tools: semantic select, mask lasso, and mask rectangle.
- Updated mask edit state to include mask asset ID and kind.
- Implemented inpaint region commands for adding, applying, and removing inpaint regions.
- Introduced new operations for lasso and semantic selection tools.
- Created UI components for candidate review and inpaint region management.
- Added tests for inpaint region commands to ensure functionality.
- Updated various components to support new inpaint features and improve user experience.

platform/browser/exportArtboardPng.ts

@@ -7,6 +7,15 @@ import { getLayerMask } from "@core/layer-mask-utils";
 import { measureTextLayer } from "@core/text-layer";
 
 export async function downloadArtboardPng(artboard: Artboard, assets: readonly Asset[]) {
+  const canvas = await renderArtboardCanvas(artboard, assets);
+  const url = canvas.toDataURL("image/png");
+  const link = document.createElement("a");
+  link.href = url;
+  link.download = `${safeFilename(artboard.name)}.png`;
+  link.click();
+}
+
+export async function renderArtboardCanvas(artboard: Artboard, assets: readonly Asset[]): Promise<HTMLCanvasElement> {
   const width = Math.max(1, Math.round(artboard.bounds.w));
   const height = Math.max(1, Math.round(artboard.bounds.h));
   const canvas = document.createElement("canvas");
@@ -27,11 +36,7 @@ export async function downloadArtboardPng(artboard: Artboard, assets: readonly A
   for (const layer of renderStack(artboard.layers)) await drawLayer(context, layer, artboard.layers, assets, artboard.bounds, { maskLayerIds });
   context.restore();
 
-  const url = canvas.toDataURL("image/png");
-  const link = document.createElement("a");
-  link.href = url;
-  link.download = `${safeFilename(artboard.name)}.png`;
-  link.click();
+  return canvas;
 }
 
 async function drawLayer(