[ironrdp-client] Wire up RDPEUSB with libusb backend

Integrate the RDPEUSB client into ironrdp-client as a working demonstration. A user should be able to redirect a local USB device to an RDP server.

**Depends on:**
- #1135
- #1137
- #1139

### Tasks
- Add --usb-device CLI flag to ironrdp-client
- Wire UrbdrcListener into DrdynvcClient using the new with_listener() API
- Connect RusbBackend to the listener; handle device plug/unplug events from a background thread feeding ADD_VIRTUAL_CHANNEL / RETRACT_DEVICE into the session
- Graceful error reporting when a device is busy or access is denied (e.g. no udev rules on Linux)

### Acceptance criteria
- ironrdp-client --usb-device 1234:5678 successfully redirects a USB device into an RDP session on a Windows server
- Device appears in Device Manager on the server
- Hot-plug: plugging a device mid-session works; unplugging cleans up without crashing