Add Freebeat Fit bike support via USB serial (issue #4822)

- New FreebeatUSB QThread: opens /dev/ttyS4 at 9600 baud 8N1 (internal UART),
  handles binary protocol decoded from APK reverse engineering:
  - 5-byte commands [startCode, action, data, checksum, 0xA0]
  - 13-byte telemetry packets with speed, RPM and resistance
  - LED heartbeat to keep bike awake
- New freebeatbike device class extending bike, with virtual bike support
- New QZSettings::freebeat_serialport setting
- QML accordion "Freebeat Bike Options" with serial port field
- Wired into bluetooth.cpp instantiation, destructor and device getter
- Added to qdomyos-zwift.pri and settings-catalog.json

Fixes #4822

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: cagnulein

src/devices/bluetooth.cpp

@@ -623,6 +623,8 @@ void bluetooth::deviceDiscovered(const QBluetoothDeviceInfo &device) {
         settings.value(QZSettings::computrainer_serialport, QZSettings::default_computrainer_serialport).toString();
     QString kettlerUsbSerialPort =
         settings.value(QZSettings::kettler_usb_serialport, QZSettings::default_kettler_usb_serialport).toString();
+    QString freebeatSerialPort =
+        settings.value(QZSettings::freebeat_serialport, QZSettings::default_freebeat_serialport).toString();
     QString csaferowerSerialPort = settings.value(QZSettings::csafe_rower, QZSettings::default_csafe_rower).toString();
     QString csafeellipticalSerialPort =
         settings.value(QZSettings::csafe_elliptical_port, QZSettings::default_csafe_elliptical_port).toString();
@@ -949,6 +951,19 @@ void bluetooth::deviceDiscovered(const QBluetoothDeviceInfo &device) {
                     emit searchingStop();
                 }
                 this->signalBluetoothDeviceConnected(kettlerUsbBike);
+            } else if (!freebeatSerialPort.isEmpty() && !freebeatBike) {
+                this->stopDiscovery();
+                freebeatBike =
+                    new freebeatbike(noWriteResistance, noHeartService, bikeResistanceOffset, bikeResistanceGain);
+                emit deviceConnected(b);
+                connect(freebeatBike, &bluetoothdevice::connectedAndDiscovered, this,
+                        &bluetooth::connectedAndDiscovered);
+                connect(freebeatBike, &freebeatbike::debug, this, &bluetooth::debug);
+                freebeatBike->deviceDiscovered(b);
+                if (this->discoveryAgent && !this->discoveryAgent->isActive()) {
+                    emit searchingStop();
+                }
+                this->signalBluetoothDeviceConnected(freebeatBike);
             } else if (!csaferowerSerialPort.isEmpty() && !csafeRower) {
                 this->stopDiscovery();
                 csafeRower = new csaferower(noWriteResistance, noHeartService, false);
@@ -4196,6 +4211,11 @@ void bluetooth::restart() {
         delete kettlerUsbBike;
         kettlerUsbBike = nullptr;
     }
+    if (freebeatBike) {
+
+        delete freebeatBike;
+        freebeatBike = nullptr;
+    }
     if (csafeRower) {
 
         delete csafeRower;
@@ -4563,6 +4583,8 @@ bluetoothdevice *bluetooth::device() {
         return computrainerBike;
     } else if (kettlerUsbBike) {
         return kettlerUsbBike;
+    } else if (freebeatBike) {
+        return freebeatBike;
     } else if (csafeRower) {
         return csafeRower;
     } else if (csafeElliptical) {

src/devices/bluetooth.h

@@ -36,6 +36,7 @@
 #ifndef Q_OS_IOS
 #include "devices/computrainerbike/computrainerbike.h"
 #include "devices/kettlerusbbike/kettlerusbbike.h"
+#include "devices/freebeatbike/freebeatbike.h"
 #include "devices/csaferower/csaferower.h"
 #include "devices/csafeelliptical/csafeelliptical.h"
 #endif
@@ -202,6 +203,7 @@ class bluetooth : public QObject, public SignalHandler {
 #ifndef Q_OS_IOS
     computrainerbike *computrainerBike = nullptr;
     kettlerusbbike *kettlerUsbBike = nullptr;
+    freebeatbike *freebeatBike = nullptr;
     csaferower *csafeRower = nullptr;
     csafeelliptical *csafeElliptical = nullptr;
 #endif