sds_add_event_listener / sds_remove_event_listener run on the foreign
caller thread and allocate Nim memory ($eventName, the listener registry
Table+seq), but unlike the ctor/dtor they never called initializeLibrary.
A foreign host (Go) migrates goroutines across OS threads, so the thread
running add_event_listener may not be the one that ran a prior entry
point; without setupForeignThreadGc its per-thread allocator region is
uninitialised and the first Nim allocation faults in the allocator.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* protect against mem leak in case of failures sending requests to ffi thread
* better cleanup if failures in createFFIContext
* avoid dangling cstring in handleRes under ARC/ORC
* better resource cleanup in destroyFFIContext
* invoke onNotResponding if failure in destroyFFIContext
* correct seq copy in alloc
* make sure the lock is init before cleanUpResources
* better possible exception handling in processReq
* guard allocSharedSeq if given seq is empty
* enhance error handling in ffi_context
* add new tests and some corrections
