The idx v4 type table supersedes the global type queue: workers no longer
enqueue every Write(Type) into a shared ConcurrentQueue during the freeze,
WriteFiles no longer drains and dedupes millions of entries, and the db file
is no longer produced. Loading old saves still reads SerializedTypes.db via
the legacy v2/v3 path.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
