Rename product, namespaces, libraries, paths, and assets from Orion/orion
to Onion/onion across the tree. TCP stack-shutdown magic is now ONIO
(0x4F4E494F) to match the corrected branding.
Move util cheats orchestration to C++ (CheatService, Repository, Applier,
IMemoryBackend, ICheatParser factory for json/shn/mc4 with ShnExt C adapter).
Drop the obsolete RELOAD_CHEATS UI/IPC path; reloads use file-signature hot
reload only. Document util cheats architecture under docs/util_arch.
Remove the old txt-index CheatManager and mc4decrypter path. Add a flat
TITLE_VERSION cheat engine supporting json/shn/mc4/ShnExt, mdbg/kdirect memory
writes, hot reload, and repo flatten install. Wire util IPC and build/link
keystone for ShnExt assembly.