The TWildcatBase.OpenConference was creating a TMsgDatabase without
populating the SDK globals, causing access violations on MwConfig.
Now calls the full Register sequence: InitWCglobal, LoadMakeWild,
BTInitIsam before opening; BTExitIsam + DisposeWCglobal on close.
test_wildcat reads conferences 0..6 from vendored testdata (copied
to /tmp/ma_wildcat so the source tree stays read-only).