refactor: remove direct trainer address assignment

lib/model/shifter_types.dart

@@ -657,18 +657,6 @@ class CentralStatus {
   }
 }
 
-List<int> parseMacToLittleEndianBytes(String macAddress) {
-  final compact = macAddress.replaceAll(':', '').replaceAll('-', '');
-  if (compact.length != 12) {
-    throw FormatException('Invalid MAC address format: $macAddress');
-  }
-  final bytes = <int>[];
-  for (int i = 0; i < compact.length; i += 2) {
-    bytes.add(int.parse(compact.substring(i, i + 2), radix: 16));
-  }
-  return bytes.reversed.toList(growable: false);
-}
-
 List<int> encodeTrainerAddress(TrainerAddress address) {
   if (address.flags < 0 || address.flags > 0xff) {
     throw FormatException('Invalid trainer address flags: ${address.flags}');

lib/service/shifter_service.dart

@@ -46,22 +46,6 @@ class ShifterService {
   static const int _gearRatioPayloadBytes = _gearRatioSlots + 1;
   static const int _gearRatioWriteMtu = 64;
 
-  Future<Result<void>> writeConnectToAddress(String bikeDeviceId) async {
-    try {
-      final payload = parseMacToLittleEndianBytes(bikeDeviceId);
-      return _requireBluetooth.writeCharacteristic(
-        buttonDeviceId,
-        universalShifterControlServiceUuid,
-        universalShifterConnectToAddrCharacteristicUuid,
-        payload,
-      );
-    } on FormatException catch (e) {
-      return bail('Could not parse bike address "$bikeDeviceId": $e');
-    } catch (e) {
-      return bail('Failed writing connect address: $e');
-    }
-  }
-
   Future<Result<void>> writeConnectToTrainerAddress(
     TrainerAddress trainerAddress,
   ) async {
@@ -107,14 +91,6 @@ class ShifterService {
     );
   }
 
-  Future<Result<void>> connectButtonToBike(String bikeDeviceId) async {
-    final addrRes = await writeConnectToAddress(bikeDeviceId);
-    if (addrRes.isErr()) {
-      return addrRes;
-    }
-    return writeCommand(UniversalShifterCommand.connectToDevice);
-  }
-
   Future<Result<void>> connectButtonToTrainer(
     TrainerAddress trainerAddress,
   ) async {