Removes a configured currency. There is no row and no delete of any kind here: the configured currencies are entries in the Rates list of the ClientGeneralSetting.MultiCurrency jsonb blob, so the manager writes back a newly projected list with that code left out, leaving the toggle and every other rate untouched. Read this before adding another write path for these entries: the old unique (ClientId, CurrencyCode) index is GONE with the table, so the database no longer refuses a duplicate currency. ClientCurrencyRules .Validate, called inside ClientCurrencyManager, is now the ONLY thing standing between a workspace and two entries for the same code carrying different rates — from which ResolveRate would take whichever happens to come first in the list and price real orders with it. A writer that skips that validation, or that appends to the list without it, reintroduces that silently at full production volume.