// Build-blocking check that the SPA build emitted the stable-named MCP-Apps// shell document. The self-host server serves `ui://executor/shell.html` by// reading this file from the SPA dist (`loadMcpAppsShellHtml`'s image-layout// candidate) — the runtime image carries no `packages/` tree for the package// dist candidates to hit — so a build without it ships an image whose// artifact resource reads all fail. Fail the build here instead. Same shape// as apps/cloud's assertion in scripts/build.mjs.import { existsSync, readFileSync } from "node:fs"; const shellAsset = new URL("../dist/assets/executor-mcp-apps-shell-stable.html", import.meta.url);if (!existsSync(shellAsset)) {  console.error(`[build] missing MCP-Apps shell asset at ${shellAsset.pathname}`);  process.exit(1);}if (!readFileSync(shellAsset, "utf8").includes('name="executor-mcp-apps-shell"')) {  console.error(`[build] ${shellAsset.pathname} is not the MCP-Apps shell document`);  process.exit(1);}