build: add Vue and Pinia to the browser build and unit tests

src/testSupport/registerVue.mjs

@@ -0,0 +1,4 @@
+import { register } from 'node:module';
+
+// Lets unit tests import single-file components (`node --import`).
+register('./vueLoader.mjs', import.meta.url);

src/testSupport/vueLoader.mjs

@@ -0,0 +1,39 @@
+import { readFile } from 'node:fs/promises';
+import { fileURLToPath } from 'node:url';
+import { compileScript, compileTemplate, parse } from 'vue/compiler-sfc';
+
+/**
+ * Compile a single-file component to an ES module for Node's test runner.
+ * Styles are dropped: tests read the global stylesheet separately.
+ */
+export function compileVueModule(source, filename) {
+  const { descriptor, errors } = parse(source, { filename });
+  if (errors.length) throw errors[0];
+  const id = filename;
+  if (descriptor.scriptSetup) {
+    return compileScript(descriptor, { id, inlineTemplate: true }).content;
+  }
+  const script = descriptor.script
+    ? compileScript(descriptor, { id }).content.replace(
+        'export default',
+        'const __sfc__ =',
+      )
+    : 'const __sfc__ = {};';
+  const template = descriptor.template
+    ? compileTemplate({ source: descriptor.template.content, filename, id })
+        .code
+    : '';
+  return `${script}\n${template}\n__sfc__.render = typeof render === 'function' ? render : __sfc__.render;\nexport default __sfc__;\n`;
+}
+
+/** Node module hook: load `.vue` files as compiled modules. */
+export async function load(url, context, nextLoad) {
+  if (!url.endsWith('.vue')) return nextLoad(url, context);
+  const filename = fileURLToPath(url);
+  const source = await readFile(filename, 'utf8');
+  return {
+    format: 'module',
+    source: compileVueModule(source, filename),
+    shortCircuit: true,
+  };
+}

src/tooling/viteBuild.test.mjs

@@ -29,7 +29,8 @@ test('explicit build inputs preserve browser-only defines, plugin order and loop
   assert.equal(config.plugins[0].enforce, 'pre');
   assert.equal(config.plugins[1].name, 'host-check');
   assert.equal(config.plugins[1].enforce, 'pre');
-  assert.equal(config.plugins[4], plugin);
+  assert.equal(config.plugins[4].name, 'vite:vue');
+  assert.equal(config.plugins[5], plugin);
   assert.equal(config.server.host, 'localhost');
   assert.equal(config.server.port, 4173);
   assert.deepEqual(config.server.allowedHosts, ['localhost', '127.0.0.1']);
@@ -103,7 +104,7 @@ test('build helper does not discover environment values or construct local provi
       undefined,
     );
     assert.deepEqual(
-      config.plugins.slice(4).map((plugin) => plugin.name),
+      config.plugins.slice(5).map((plugin) => plugin.name),
       ['embed-framing', 'panel-build'],
     );
   } finally {
@@ -117,7 +118,7 @@ test('root config retains existing named exports and standalone provider order',
     assert.equal(compatibility[name], value, name);
   const config = standaloneConfig({ mode: 'test' });
   const standaloneProviders = config.plugins
-    .slice(4, -6)
+    .slice(5, -6)
     .map((plugin) => plugin.name);
   assert.equal(
     standaloneProviders.filter((name) => name === 'gemini-live-proxy').length,