Link test: optional @host on the launch hook; summary script for the Orin's results

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz

lib/main.dart

@@ -18,10 +18,14 @@ Future<void> main() async {
   await usb.bindFor(Uri.parse(defaultUrl));
   final boundary = Boundary(defaultUrl)..start();
   final linkTest = LinkTest(usb);
-  // Development hook: `am start ... --es linktest <label>` runs the test on the gateway's host.
-  Future<void> runLinkTest(String label) async {
+  // Development hook: `am start ... --es linktest <label>[@<host>]` runs the test,
+  // on the gateway's host unless one is given.
+  Future<void> runLinkTest(String request) async {
+    final at = request.indexOf('@');
+    final label = at < 0 ? request : request.substring(0, at);
+    final host = at < 0 ? Uri.parse(boundary.url).host : request.substring(at + 1);
     navigatorKey.currentState?.push(MaterialPageRoute<void>(builder: (_) => linkTestPage(boundary, linkTest, usb)));
-    await linkTest.run(Uri.parse(boundary.url).host, label);
+    await linkTest.run(host, label);
     await usb.bindFor(Uri.parse(boundary.url));
   }