test(frontend): garde-fou sur le transport des bundles construits (#74 Q1)

Vérifie sur les artefacts réels que `dist` résout `tauri` et `dist-web`
`http`, en lisant le marqueur `__IDEA_TRANSPORT__` des assets JS émis. La
régression de #74 était invisible aux tests unitaires : elle vivait dans la
conf de build et de packaging, pas dans le code testé.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/scripts/assert-bundle-transport.mjs

@@ -0,0 +1,78 @@
+import { readdir, readFile } from "node:fs/promises";
+import { join } from "node:path";
+
+const EXPECTED_TRANSPORT_BY_DIR = new Map([
+  ["dist", "tauri"],
+  ["dist-web", "http"],
+]);
+
+async function readJavaScriptAssets(buildDir) {
+  const assetsDir = join(process.cwd(), buildDir, "assets");
+  let entries;
+  try {
+    entries = await readdir(assetsDir, { withFileTypes: true });
+  } catch (error) {
+    throw new Error(
+      `Cannot read ${assetsDir}. Run npm run build:bundle before this check. ${error.message}`,
+    );
+  }
+
+  const files = entries
+    .filter((entry) => entry.isFile() && entry.name.endsWith(".js"))
+    .map((entry) => join(assetsDir, entry.name));
+
+  if (files.length === 0) {
+    throw new Error(`No JavaScript assets found in ${assetsDir}.`);
+  }
+
+  return Promise.all(
+    files.map(async (file) => ({
+      file,
+      source: await readFile(file, "utf8"),
+    })),
+  );
+}
+
+function transportMarkers(source) {
+  return [...source.matchAll(/__IDEA_TRANSPORT__="([a-z]+)"/g)].map(
+    (match) => match[1],
+  );
+}
+
+async function assertBundleTransport(buildDir, expectedTransport) {
+  const assets = await readJavaScriptAssets(buildDir);
+  const markers = assets.flatMap(({ file, source }) =>
+    transportMarkers(source).map((transport) => ({ file, transport })),
+  );
+
+  if (markers.length === 0) {
+    throw new Error(
+      `${buildDir} does not publish a __IDEA_TRANSPORT__ marker in its built JavaScript assets.`,
+    );
+  }
+
+  const unexpected = markers.filter(
+    ({ transport }) => transport !== expectedTransport,
+  );
+  if (unexpected.length > 0) {
+    const details = unexpected
+      .map(({ file, transport }) => `${file}: ${transport}`)
+      .join("\n");
+    throw new Error(
+      `${buildDir} resolves the wrong transport; expected ${expectedTransport}.\n${details}`,
+    );
+  }
+
+  console.log(
+    `${buildDir}: __IDEA_TRANSPORT__="${expectedTransport}" (${markers.length} marker${markers.length === 1 ? "" : "s"})`,
+  );
+}
+
+try {
+  for (const [buildDir, expectedTransport] of EXPECTED_TRANSPORT_BY_DIR) {
+    await assertBundleTransport(buildDir, expectedTransport);
+  }
+} catch (error) {
+  console.error(error instanceof Error ? error.message : error);
+  process.exitCode = 1;
+}