Target resolution helpers for direct-message fanout.
@spec drop_base_alias_targets(term()) :: [String.t()]
@spec filter_prekey_bundles_for_identity(map(), String.t()) :: map()
@spec list_session_targets_for_jid(term() | nil, String.t()) :: [String.t()]
@spec resolve_encryption_targets(term() | nil, String.t(), map(), list() | nil) :: [ String.t() ]
@spec resolve_own_device_targets(term() | nil, String.t(), integer(), list() | nil) :: [String.t()]