Merge remote-tracking branch 'origin/zmq-radio-3' into integration_2026_w17 (!3975)

ZMQ radio

This is a zmq radio implementation that attempts to integrate NR UE with
the ocudu project.

OAI integration status:
This can currently be used to connect OAI gnb and OAI UE.

Compilation:
cmake --build . --target nr-softmodem nr-uesoftmodem ldpc params_libconfig zmq_radio

Running
- gNB command:
sudo ./nr-softmodem -O ../targets/PROJECTS/GENERIC-NR-5GC/CONF/gnb.sa.band78.fr1.106PRB.usrpb210.conf --gNBs.[0].min_rxtxtime 6 --device.name zmq_radio --zmq.[0].tx_channels tcp://127.0.0.1:4556 --zmq.[0].rx_channels tcp://127.0.0.1:4557

- UE command:
sudo ./nr-uesoftmodem -r 106 --numerology 1 --band 78 -C 3619200000 --ssb 516 --device.name zmq_radio --zmq.[0].tx_channels tcp://127.0.0.1:4557 --zmq.[0].rx_channels tcp://127.0.0.1:4556

A new CI testcase for 2x2 configuration was added.

OCUDU integration status:
The OAI NR UE enters RRC Connected state.

For more details, please refer to the description of MR !3975.

doc/README.md

@@ -108,6 +108,7 @@ Some directories under `radio` contain READMEs:
 - [fhi_72](../radio/fhi_72/README.md)
 - [vrtsim](../radio/vrtsim/README.md)
 - [rf_emulator](../radio/emulator/README.md)
+- [zmq](../radio/zmq/README.md)
 
 The other SDRs (AW2S, LimeSDR, ...) have no READMEs.