fix(ci): support memind-ci-mac runner and stabilize acceptance HTTP server

The self-hosted macOS runner cannot run apt-get or install Linux-only Sharp
packages; gate CI on sqlite availability and platform-specific Sharp setup.
Also wait for ephemeral Express listen before fetch to avoid AUTH-08 flakes.

Co-authored-by: Cursor <cursoragent@cursor.com>

page-data-acceptance.test.mjs

@@ -98,8 +98,17 @@ function buildApp(workspaceRoot, pool = createPool('public')) {
   return app;
 }
 
-async function request(app, method, url, { body, headers } = {}) {
+async function listenEphemeral(app) {
   const server = app.listen(0);
+  await new Promise((resolve, reject) => {
+    server.once('listening', resolve);
+    server.once('error', reject);
+  });
+  return server;
+}
+
+async function request(app, method, url, { body, headers } = {}) {
+  const server = await listenEphemeral(app);
   try {
     const { port } = server.address();
     const response = await fetch(`http://127.0.0.1:${port}${url}`, {