Merge remote-tracking branch 'origin/shm-radio' into integration_2025_w13 (!3260)

Shared memory realtime radio simulation

Realtime and near-realtime RFSimulator alternative without channel modelling.
The purpose of this library is to allow realtime simulation of gNB and nrUE.

The library is loaded using --device.name vrtsim. The server side (gNB) should
also configure --vrtsim.role server and --vrtsim.timescale according to
requirements.

Limitations:
- Only 1UE-to-1gNB connection supported

Future work:
- Telnet API

openair1/SIMULATION/TOOLS/sim.h

@@ -50,6 +50,7 @@ typedef enum {
 #define CHANMODEL_FREE_RSQRT_6     1<<1
 #define CHANMODEL_FREE_RSQRT_NTAPS 1<<2
 #define CHANMODEL_FREE_AMPS        1<<3
+#define SHR3 (jz = jsr, jsr ^= (jsr << 13), jsr ^= (jsr >> 17), jsr ^= (jsr << 5), jz + jsr)
 
 typedef enum {
   CORR_LEVEL_LOW,