fix: Give a warning when using Safari for CLI login

src/server/HelixServer.js

@@ -47,6 +47,23 @@ export class HelixServer extends BaseServer {
   }
 
   async handleLogin(req, res) {
+    const userAgent = req.headers['user-agent']?.toLowerCase();
+    if (userAgent?.includes('safari') && !userAgent?.includes('chrome')) {
+      res.status(403).send(`
+<p>It looks like you are using Safari to login via the AEM CLI...</p>
+<p>Unfortunately, the login flow is not supported at the moment in Safari. You can follow the progress at the following <a href="https://github.com/adobe/helix-cli/issues/2498">Github issue</a>.</p>
+<p>Please use Google Chrome or Mozilla Firefox in the meantime for login.</p>
+<p>To avoid changing your default browser, you can:</p>
+<ol>
+  <li>Start the CLI with the <strong>--no-open</strong> option to avoid opening the browser automatically</li>
+  <li>Open  Chrome or Firefox and login via the CLI</li>
+  <li>Close the CLI and start it again normally</li>
+</ol>
+<p>Once you are logged in, the token is available for 24h and you can do the rest of your work in your favorite browser.</p>
+`);
+      return;
+    }
+
     // disable autologin if login was called at least once
     this._autoLogin = false;
     // clear any previous login errors