Add web serial support and USB tests

test/services/usb_serial_frame_codec_test.dart

@@ -0,0 +1,84 @@
+import 'dart:typed_data';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:meshcore_open/services/usb_serial_frame_codec.dart';
+
+void main() {
+  test('wrapUsbSerialTxFrame prefixes tx header and payload length', () {
+    final packet = wrapUsbSerialTxFrame(Uint8List.fromList(<int>[0x16, 0x03]));
+
+    expect(
+      packet,
+      orderedEquals(<int>[usbSerialTxFrameStart, 0x02, 0x00, 0x16, 0x03]),
+    );
+  });
+
+  test('UsbSerialFrameDecoder buffers partial frames until complete', () {
+    final decoder = UsbSerialFrameDecoder();
+
+    final firstChunk = decoder.ingest(
+      Uint8List.fromList(<int>[usbSerialRxFrameStart, 0x03]),
+    );
+    final secondChunk = decoder.ingest(
+      Uint8List.fromList(<int>[0x00, 0x05, 0x06, 0x07]),
+    );
+
+    expect(firstChunk, isEmpty);
+    expect(secondChunk, hasLength(1));
+    expect(secondChunk.single.isRxFrame, isTrue);
+    expect(secondChunk.single.payload, orderedEquals(<int>[0x05, 0x06, 0x07]));
+  });
+
+  test(
+    'UsbSerialFrameDecoder drops leading noise and parses multiple frames',
+    () {
+      final decoder = UsbSerialFrameDecoder();
+
+      final packets = decoder.ingest(
+        Uint8List.fromList(<int>[
+          0x00,
+          0x01,
+          usbSerialRxFrameStart,
+          0x01,
+          0x00,
+          0x55,
+          usbSerialRxFrameStart,
+          0x02,
+          0x00,
+          0x66,
+          0x77,
+        ]),
+      );
+
+      expect(packets, hasLength(2));
+      expect(packets[0].payload, orderedEquals(<int>[0x55]));
+      expect(packets[1].payload, orderedEquals(<int>[0x66, 0x77]));
+    },
+  );
+
+  test(
+    'UsbSerialFrameDecoder preserves tx packets so caller can ignore them',
+    () {
+      final decoder = UsbSerialFrameDecoder();
+
+      final packets = decoder.ingest(
+        Uint8List.fromList(<int>[
+          usbSerialTxFrameStart,
+          0x01,
+          0x00,
+          0x22,
+          usbSerialRxFrameStart,
+          0x01,
+          0x00,
+          0x33,
+        ]),
+      );
+
+      expect(packets, hasLength(2));
+      expect(packets[0].isRxFrame, isFalse);
+      expect(packets[0].payload, orderedEquals(<int>[0x22]));
+      expect(packets[1].isRxFrame, isTrue);
+      expect(packets[1].payload, orderedEquals(<int>[0x33]));
+    },
+  );
+}

test/utils/usb_port_labels_test.dart

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+import 'package:flutter_test/flutter_test.dart';
+import 'package:meshcore_open/utils/usb_port_labels.dart';
+
+void main() {
+  test('normalizeUsbPortName strips friendly suffix from composite label', () {
+    expect(
+      normalizeUsbPortName(
+        'COM6 - USB Serial Device (COM6) - USB\\VID_2886&PID_1667',
+      ),
+      'COM6',
+    );
+  });
+
+  test('friendlyUsbPortName prefers suffix when present', () {
+    expect(
+      friendlyUsbPortName(
+        'COM6 - USB Serial Device (COM6) - USB\\VID_2886&PID_1667',
+      ),
+      'USB Serial Device (COM6) - USB\\VID_2886&PID_1667',
+    );
+  });
+
+  test(
+    'friendlyUsbPortName falls back to normalized port when suffix is empty',
+    () {
+      expect(friendlyUsbPortName('COM6 - '), 'COM6');
+    },
+  );
+
+  test('describeWebUsbPort uses known VID/PID names when available', () {
+    expect(
+      describeWebUsbPort(
+        vendorId: 0x2886,
+        productId: 0x1667,
+        knownUsbNames: const <String, String>{
+          '2886:1667': 'Seeed Wio Tracker L1',
+        },
+      ),
+      'Seeed Wio Tracker L1 (VID:2886 PID:1667)',
+    );
+  });
+
+  test('describeWebUsbPort falls back to generic label for unknown device', () {
+    expect(
+      describeWebUsbPort(vendorId: 0x1234, productId: 0x5678),
+      'Web Serial Device (VID:1234 PID:5678)',
+    );
+  });
+
+  test('describeWebUsbPort returns chooser label when no usb ids exist', () {
+    expect(
+      describeWebUsbPort(vendorId: null, productId: null),
+      usbRequestPortLabel,
+    );
+  });
+
+  test('buildUsbDisplayLabel appends device-reported name when available', () {
+    expect(
+      buildUsbDisplayLabel(
+        basePortLabel: 'Seeed Wio Tracker L1 (VID:2886 PID:1667)',
+        deviceName: 'KD3CGK mesh-utility.org',
+      ),
+      'Seeed Wio Tracker L1 (VID:2886 PID:1667) - KD3CGK mesh-utility.org',
+    );
+  });
+
+  test('buildUsbDisplayLabel keeps base label when custom name is blank', () {
+    expect(
+      buildUsbDisplayLabel(
+        basePortLabel: 'Seeed Wio Tracker L1 (VID:2886 PID:1667)',
+        deviceName: '   ',
+      ),
+      'Seeed Wio Tracker L1 (VID:2886 PID:1667)',
+    );
+  });
+}