Remove ComPortController finalizer and run deactivation on program shutdown

[Copilot]

ComPortController could throw NullReferenceException during shutdown from its finalizer path. The controller was performing COM-port cleanup in ~ComPortController() even when no port instance existed.

• Finalization cleanup moved out of GC path

  • Removed ~ComPortController() to eliminate shutdown-time finalizer exceptions and avoid cleanup work during object finalization.

• Explicit shutdown behavior in Deactivate()

  • Kept cleanup in the explicit lifecycle path by unsubscribing SerialDataReceived in Deactivate().
  • Treated Port == null as already deactivated (return true) instead of a failure condition.

• Program shutdown integration

  • Registered ComPortController to CrestronEnvironment.ProgramStatusEventHandler after successful initialization.
  • Calls Deactivate() when the program enters Stopping so COM port cleanup runs during system shutdown without relying on finalization.
  • Deactivate() now unsubscribes from the program status event and is guarded to be idempotent/thread-safe to prevent duplicate deactivation work.

• Net effect

  • No COM port + shutdown now safely no-ops.
  • Existing unregister behavior is unchanged when a valid port exists.
  • COM port controllers now participate in the normal program stopping lifecycle.

public override bool Deactivate()
{
    lock (_deactivateLock)
    {
        if (_isDeactivated)
            return true;

        _isDeactivated = true;
    }

    CrestronEnvironment.ProgramStatusEventHandler -= CrestronEnvironment_ProgramStatusEventHandler;

    if (Port == null)
        return true;

    Port.SerialDataReceived -= Port_SerialDataReceived;
    return Port.UnRegister() == eDeviceRegistrationUnRegistrationResponse.Success;
}

[ngenovese11]

@copilot can we register to the Program shutting down event (may need to reference other classes for this) and call deactivate at shutdown

[Copilot]

@copilot can we register to the Program shutting down event (may need to reference other classes for this) and call deactivate at shutdown

Implemented in d4f1fec. ComPortController now subscribes to CrestronEnvironment.ProgramStatusEventHandler and calls Deactivate() on Stopping, with idempotent deactivation and cleanup/unsubscribe handling.

[Copilot]

Pull request overview

This PR updates ComPortController shutdown behavior to avoid COM-port cleanup running in the GC finalizer path and instead perform cleanup explicitly during program shutdown (eProgramStatusEventType.Stopping). The goal is to prevent shutdown-time exceptions and make deactivation safer and repeatable.

Changes:

• Removed the ~ComPortController() finalizer-based cleanup.
• Added a CrestronEnvironment.ProgramStatusEventHandler hook to call Deactivate() on program Stopping.
• Made Deactivate() guarded with a lock/flag and treat Port == null as already deactivated, while also unsubscribing SerialDataReceived.

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