[Jiu-xiao]

An item of USB.<instance>.cdc in libxr_config.yaml may set interface. It becomes the control and data interface name of that CDCUart, so a host can tell apart CDCs that share VID:PID.

USB:
  usb_otg_hs:
    enable: true
    cdc:
    - {tx_fifo_size: 128, rx_fifo_size: 128, queue_size: 3, interface: Console}
    - {tx_fifo_size: 128, rx_fifo_size: 128, queue_size: 3, interface: Telemetry}

What changes

• _check_cdc: interface is optional and must be a string; it gets no default.
• The generated USB::CDCUart takes the name twice (control_interface_string, data_interface_string); double quotes in the name are escaped.
• Items without interface generate the same code as before (LibXR defaults XRUSB CDC Control / XRUSB CDC Data).
• README: the interface key with an example.

The two constructor arguments exist in CDCUart on LibXR master (V2.0.0) and dev.

Verification

• python -m unittest discover -s tests -p "test_*.py": 507 tests OK (6 skipped), including the new cases in tests/test_generator_code_stm32.py; ruff check and ruff format --check clean.

[Jiu-xiao]

Duplicate of #26 (same patch, identical tree after merge); its CI run on the merged tree passed and #26 was merged.