Gio's GioView.onDestroyView sends ViewEvent{View: 0} as its detach
signal when the view is destroyed — i.e. the activity going away on a
recents-wipe. handleEvent passed that zero straight through to
InitPgp/registerFragment, whose GetObjectClass(null) aborts the process
(JNI DETECTED ERROR: java_object == null in call to GetObjectClass).
Guard on both sides: handleEvent ignores the View == 0 detach signal
(a re-attach arrives as a fresh event with a live view), InitPgp
returns early on a zero view so unfiltered callers are covered, and
registerFragment null-checks as defense in depth. Same fix as pad
(fdbffc9); verified there on a Pixel 9 Pro / Android 17 where the
recents swipe used to crash the app.
