Pick storage by lifetime and ownership

Storage	Mutable	Survives reload/power	Scope	Main cost
Runtime int / array	Yes	No	Current script run	variable slots
define / enum	No	compiled into code	source/global	no runtime slot
Const/data array	No	part of script	current compiled script	bytecode/data bytes
SPVAR	Yes	Yes	private to one memory slot	persistent write
BVAR	Yes	Yes after commit	indexed binary store	BVAR range/commit

Document who owns every persistent slot/index. "Unused today" is not a schema.