fix(iso): add libnvidia-ptxjitcompiler + ldconfig for PTX JIT and NCCL

- build-nvidia-module.sh: copy libnvidia-ptxjitcompiler.so.* alongside
  libcuda/libnvidia-ml — required by cuModuleLoadDataEx for PTX JIT.
  Without it: CUDA_ERROR_JIT_COMPILER_NOT_FOUND at runtime.
  Cache check updated to force rebuild when ptxjitcompiler is missing.
- bee-nvidia-load: run ldconfig after module load so that NVIDIA/NCCL
  libs injected into /usr/lib/ are visible to dlopen() callers.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

iso/overlay/usr/local/bin/bee-nvidia-load

@@ -100,4 +100,9 @@ if [ -n "$uvm_major" ]; then
     mknod -m 666 /dev/nvidia-uvm-tools c "$uvm_major" 1 || true
 fi
 
+# Refresh dynamic linker cache so that NVIDIA/NCCL libs injected into /usr/lib/
+# are visible to dlopen() calls (libcuda, libnvidia-ptxjitcompiler, libnccl, etc.)
+ldconfig 2>/dev/null || true
+log "ldconfig refreshed"
+
 log "done"