refactor(tests): centralize test harness boilerplate into bundle.mjs helper

tests/run-editor-test.mjs

@@ -1,11 +1,10 @@
 // Runner for the Tiptap editor test. Sets up a jsdom DOM, then dynamically
 // imports the bundled editor module so Tiptap sees a browser-like environment.
-import esbuild from "esbuild";
 import fs from "fs";
 import os from "os";
 import path from "path";
-import url from "url";
 import { JSDOM } from "jsdom";
+import { bundleForTest } from "./helpers/bundle.mjs";
 
 const dom = new JSDOM("<!DOCTYPE html><html><body></body></html>", {
   pretendToBeVisual: true,
@@ -24,19 +23,10 @@ g.DOMParser = window.DOMParser;
 g.requestAnimationFrame = (cb) => setTimeout(cb, 0);
 g.cancelAnimationFrame = (id) => clearTimeout(id);
 
-const out = path.join(os.tmpdir(), `folio-editor-${process.pid}.mjs`);
-const entry = path.resolve("tests/.folio-editor-test-entry.ts");
-await esbuild.build({
-  entryPoints: [entry],
-  bundle: true,
-  platform: "node",
-  format: "esm",
-  outfile: out,
-  write: true,
-  logLevel: "silent",
+const { mod, cleanupBundle } = await bundleForTest({
+  name: "folio-editor",
+  entryPoints: ["tests/.folio-editor-test-entry.ts"],
 });
-
-const mod = await import(url.pathToFileURL(out).href);
 const {
   createTiptapEditor,
   runCommand,
@@ -235,7 +225,7 @@ ok(
   "standalone Highlight button applies a default highlight to the selection"
 );
 
-fs.rmSync(out, { force: true });
+cleanupBundle();
 fs.rmSync(book, { recursive: true, force: true });
 
 console.log(