CreateClient: missing NULL check after malloc() for rcl_client_t (CWE-476) #1616

Description

CreateClient in src/rcl_client_bindings.cpp allocates memory for rcl_client_t using malloc() without checking whether the allocation succeeded:

rcl_client_t* client =
    reinterpret_cast<rcl_client_t*>(malloc(sizeof(rcl_client_t)));
*client = rcl_get_zero_initialized_client();  // NULL deref if malloc failed

If malloc() returns NULL (e.g. under memory exhaustion), the very next line dereferences the NULL pointer, causing a segmentation fault and crashing the process.

Reference: CWE-476: NULL Pointer Dereference

Fix

Addressed by #1613, which adds a NULL check immediately after the malloc() call, throwing a JS-visible error instead of crashing when allocation fails.