NethLink: with physical phone transfer from NethCTI Operators panel does not work

[mgarra]

Description:
When NethLink is configured with a physical phone as the main device, transferring an active call from the Operators panel in NethCTI does not work.

Steps to reproduce:

1. Configure NethLink with a physical phone as the main device.
2. Make or receive a call.
3. In the NethCTI Operators panel, click on the desired user and then on the "Transfer" button.
4. Nothing happens, and no error is shown in the browser console.

Expected behavior:
The active call should be transferred to the selected user.

Current behavior:
The transfer does not take place, and there is no visual feedback or error in the browser console.
It appears that the action triggered by the button does not recognize the nethlink:transfer protocol.

Additional notes:

No relevant logs appear in the browser JavaScript console.

The issue only occurs when the main device is set to a physical phone.