  Long gamma-ray bursts (GRBs) associated with supernovae and short GRBs with
Extended Emission (SGRBEE) from mergers are probably powered by black holes as
a common inner engine, as their prompt GRB emission satisfies the same Amati
correlation in the $E_{p,i}-E_{iso}$ plane. We introduce modified Bardeen
equations to identify hyper-accretion driving newly formed black holes in
core-collapse supernovae to near-extremal spin as a precursor to prompt GRB
emission. Subsequent spin-down is observed in the BATSE catalog of long GRBs.
Spin-down provides a natural unification of long durations associated with the
lifetime of black hole spin for normal long GRBs and SGRBEEs, given the absence
of major fallback matter in mergers. The results point to major emissions
unseen in high frequency gravitational waves. A novel matched filtering method
is described for LIGO-Virgo and KAGRA broadband probes of nearby core-collapse
supernovae at essentially maximal sensitivity.
