fix: restore server XLS roster conversion

tools/repository-hygiene.test.mjs

@@ -323,3 +323,9 @@ test('single-source and generated-output boundaries remain explicit', async () =
   assert.ok(!existsSync(path.join(DIST, 'control-plane')));
   assert.ok(!existsSync(path.join(DIST, 'ltjt-order-assistant.zip')));
 });
+
+test('runtime image includes both LibreOffice document converters', async () => {
+  const dockerfile = await readFile(path.join(ROOT, 'Dockerfile'), 'utf8');
+  assert.match(dockerfile, /apt-get install[^\n]*libreoffice-calc/u);
+  assert.match(dockerfile, /apt-get install[^\n]*libreoffice-writer/u);
+});