Starter display: boundary v0 client, readout, mark button, CI

Connects to svc-gw over one WebSocket, heartbeats, treats timeout_ms of
silence as a dead link, and retries commands under the same id until acked.
Shows link state, signals with stale/null/missing told apart, the raw stream,
a mock banner on the surface, and a Mark button that stamps the recording.
Android: keeps the screen on and binds the process to the USB NCM network
when the gateway is on it. CI mirrors android-stuff's host-mode runner setup.

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

test/boundary_test.dart

@@ -0,0 +1,94 @@
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:display/boundary.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+/// A minimal stand-in for svc-gw: hello, then whatever the test sends.
+class FakeGateway {
+  late HttpServer server;
+  final sockets = <WebSocket>[];
+  final received = <Map<String, dynamic>>[];
+  bool ackCommands = true;
+
+  Future<void> start({bool mock = false}) async {
+    server = await HttpServer.bind(InternetAddress.loopbackIPv4, 0);
+    server.transform(WebSocketTransformer()).listen((ws) {
+      sockets.add(ws);
+      ws.add(jsonEncode({
+        't': 'hello', 'proto': 0, 'server': 'fake', 'host': 'test', 'source': mock ? 'mock' : 'none',
+        'mock': mock, 'hb_ms': 100, 'timeout_ms': 400,
+      }));
+      ws.listen((raw) {
+        final m = jsonDecode(raw as String) as Map<String, dynamic>;
+        received.add(m);
+        if (m['t'] == 'cmd' && ackCommands) {
+          ws.add(jsonEncode({'t': 'ack', 'id': m['id'], 'ok': true, 'detail': 'ok'}));
+        }
+      });
+    });
+  }
+
+  String get url => 'ws://127.0.0.1:${server.port}/';
+}
+
+Future<void> until(bool Function() cond, {Duration timeout = const Duration(seconds: 5)}) async {
+  final end = DateTime.now().add(timeout);
+  while (!cond()) {
+    if (DateTime.now().isAfter(end)) throw TimeoutException('condition not met');
+    await Future<void>.delayed(const Duration(milliseconds: 20));
+  }
+}
+
+void main() {
+  test('connects, takes state, flags mock, heartbeats', () async {
+    final gw = FakeGateway();
+    await gw.start(mock: true);
+    final b = Boundary(gw.url)..start();
+    await until(() => b.state == LinkState.up);
+    expect(b.mock, isTrue);
+    gw.sockets.first.add(jsonEncode({
+      't': 'state',
+      'seq': 1,
+      'signals': {
+        'engine_rpm': {'timestamp': 0, 'monotonic': 0, 'value': 820, 'unit': 'rpm', 'mock': true},
+      },
+    }));
+    await until(() => b.signals.containsKey('engine_rpm'));
+    await until(() => gw.received.where((m) => m['t'] == 'hb').length >= 2);
+    await b.stop();
+    await gw.server.close(force: true);
+  });
+
+  test('silence past timeout_ms drops the link and reconnects', () async {
+    final gw = FakeGateway();
+    await gw.start();
+    final b = Boundary(gw.url)..start();
+    await until(() => b.state == LinkState.up);
+    // The fake never sends heartbeats, so the watchdog must fire after 400 ms.
+    await until(() => gw.sockets.length >= 2, timeout: const Duration(seconds: 4));
+    await b.stop();
+    await gw.server.close(force: true);
+  });
+
+  test('commands are retried under the same id until acked', () async {
+    final gw = FakeGateway()..ackCommands = false;
+    await gw.start();
+    final b = Boundary(gw.url)..start();
+    await until(() => b.state == LinkState.up);
+    final id = b.command('mark', {'text': 'brake'});
+    await until(() => gw.received.any((m) => m['t'] == 'cmd'));
+    // Drop the connection unacked; the command must be resent after reconnect.
+    gw.ackCommands = true;
+    await gw.sockets.first.close();
+    await until(() => b.pending.isEmpty);
+    final sent = gw.received.where((m) => m['t'] == 'cmd').toList();
+    expect(sent.length, greaterThanOrEqualTo(2));
+    expect(sent.every((m) => m['id'] == id), isTrue);
+    expect(sent.last['args']['delay_ms'], greaterThan(0));
+    expect(b.acks.first.ok, isTrue);
+    await b.stop();
+    await gw.server.close(force: true);
+  });
+}

test/widget_test.dart

@@ -1,30 +0,0 @@
-// This is a basic Flutter widget test.
-//
-// To perform an interaction with a widget in your test, use the WidgetTester
-// utility in the flutter_test package. For example, you can send tap and scroll
-// gestures. You can also use WidgetTester to find child widgets in the widget
-// tree, read text, and verify that the values of widget properties are correct.
-
-import 'package:flutter/material.dart';
-import 'package:flutter_test/flutter_test.dart';
-
-import 'package:display/main.dart';
-
-void main() {
-  testWidgets('Counter increments smoke test', (WidgetTester tester) async {
-    // Build our app and trigger a frame.
-    await tester.pumpWidget(const MyApp());
-
-    // Verify that our counter starts at 0.
-    expect(find.text('0'), findsOneWidget);
-    expect(find.text('1'), findsNothing);
-
-    // Tap the '+' icon and trigger a frame.
-    await tester.tap(find.byIcon(Icons.add));
-    await tester.pump();
-
-    // Verify that our counter has incremented.
-    expect(find.text('0'), findsNothing);
-    expect(find.text('1'), findsOneWidget);
-  });
-}