[Fix] Force numpy>=2.4.1 in --install to escape OpenBLAS atfork SIGSEGV

The setup.py constraint "numpy>=2,!=2.3.5" landed in isaac-sim#5642 is silently
overridden during isaaclab.sh --install because pip resolves each
submodule install independently:

  - isaaclab            -> numpy stays at 2.3.1 (already satisfied)
  - isaaclab_mimic[h5py]-> numpy 1.26.4 (h5py wheel ABI)
  - isaaclab_rl         -> numpy 2.4.5
  - isaaclab_teleop[dex-retargeting] -> numpy 2.3.5 (cmeel-boost <2.4 cap)
  - isaaclab_visualizers-> numpy 2.3.4
  - isaaclab_mimic[robomimic] -> numpy 1.26.4
  - _ensure_pink_ik_dependencies_installed force-reinstall -> numpy 2.3.5

The final pin-pink force-reinstall sees only pin-pink's numpy>=1.19 plus
cmeel-boost's numpy<2.4 cap and lands on numpy 2.3.5 - the exact release
whose vendored OpenBLAS (libscipy_openblas64_-fdde5778.so) registers a
buggy pthread_atfork handler that SIGSEGVs Kit's libomni.platforminfo
fork() during SimulationApp startup.

After the pin-pink force-reinstall, append one more pip invocation that
explicitly upgrades numpy to >= 2.4.1. pip prints a resolver warning
about cmeel-boost's cap but installs numpy 2.4.5 anyway; numpy's stable
C ABI (numpy >= 2.0) keeps cmeel's compiled extensions (libpinocchio,
libcoal, ...) working at runtime. The atfork fix landed upstream in
numpy 2.4.1, so the entire 2.3.x risk class is bypassed.

Validated locally on env_isaaclab_test (numpy 2.4.5 + pinocchio 3.9.0 +
pin 3.9.0 + daqp + qpsolvers):
- import numpy, pinocchio, pink, daqp: OK
- Bundled OpenBLAS hash: -32a4b2a6 (not the broken -fdde5778)
- IsaacLab Pink IK unit tests: 54/54 pass
  (test_pink_ik_components.py 21/21, test_local_frame_task.py 24/24,
   test_null_space_posture_task.py 9/9)

Related: numpy/numpy#30092, OpenMathLib/OpenBLAS#5520

Author: hujc7

source/isaaclab/isaaclab/cli/commands/install.py

@@ -223,6 +223,24 @@ def _ensure_pink_ik_dependencies_installed(python_exe: str, pip_cmd: list[str],
             f"{install_result.returncode}). The pink IK controller and its tests will not be"
             " usable until ``pin pin-pink==3.1.0 daqp==0.8.5`` is installed manually."
         )
+        return
+
+    # Force numpy >= 2.4.1 to bypass the OpenBLAS atfork SIGSEGV that crashes
+    # Kit's libomni.platforminfo fork() with numpy 2.3.5's vendored OpenBLAS
+    # (libscipy_openblas64_-fdde5778.so). pip is asked to ignore cmeel-boost's
+    # `numpy<2.4` cap; numpy's stable C ABI keeps cmeel's compiled extensions
+    # (libpinocchio, libcoal, ...) working at runtime. See numpy/numpy#30092,
+    # OpenMathLib/OpenBLAS#5520, OMPE-92261.
+    print_info("Forcing numpy >= 2.4.1 to skip the OpenBLAS atfork SIGSEGV in numpy 2.3.5.")
+    numpy_upgrade = run_command(
+        pip_cmd + ["install", "--upgrade", "numpy>=2.4.1"],
+        check=False,
+    )
+    if numpy_upgrade.returncode != 0:
+        print_warning(
+            f"Forcing numpy >= 2.4.1 failed (returncode {numpy_upgrade.returncode}). "
+            "Kit fork() may SIGSEGV on numpy 2.3.5's vendored OpenBLAS."
+        )
 
 
 def _ensure_cuda_torch() -> None: