I've only ever heard "hold for release" at non-towered airports when
using an RCO or when working via FSS. Then, it's part of the clearance
and needs to be read back. At a towered airport, I don't see the point
in him telling you "hold for release" as ATC has to clear you on to
the runway in any case. I've some times been told "Hold short --
awaiting IFR release" when I've called #1 and ready to go at a towered
airport, but that's really just a hold short instruction with a reason
attached, and even then, it's not like your situation where you were
given the hold pretaxi.