SidebarMemberSection read role name->id from a parallel roles.store that
nothing ever wrote to — only channels.store.setRoles is updated by the
dispatcher on `ready`. Repoint the reader at channels.store and delete the
dead roles.store (its setRoles/getRoleIdByName coverage already lives in
channels.store.test.ts). Adds a regression test pinning that the member UI
resolves role ids from the store the dispatcher writes.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>