fix: protect Lua event registration calls

[nkbeast]

Summary

• route the Lua event:add call through the existing traceback-aware protected call helper
• propagate registration errors to the calling Lua script instead of allowing an unprotected panic

Validation

• source check: no raw lua_call remains in LuaBinding.cpp
• git diff --check — passed
• CMake configure was attempted but this environment lacks the system CURL development library (CURL_LIBRARY/CURL_INCLUDE_DIR)

[eduardodoria]

Thanks