pstn_in_denied, the personal-DID owner denial, and pstn_personal_denied_group
fell straight to a bare Hangup() on an unanswered channel instead of
Busy(15) like every other denial path in this file (outbound tier/number/
intl/killswitch). A bare Hangup() doesn't map to "486 Busy Here" the way
Busy() does, so a denied inbound call (wrong tier, number not on the
approved list, group membership mismatch) could sound like a generic
call-failed/fast-busy rather than a clean busy signal - easy to mistake
for a broken permission check when the real issue is a config mismatch.
Also added a NoOp() logging the resolved group name, caller ID, and
PSTN_RING_LIST right after the group-ring SHELL() call, so the next test
of a group-assigned personal number shows directly (via the Asterisk
console/full log) whether the ring list came back empty - and if so, which
of group membership, tier, or allowed_numbers to check next - instead of
requiring another guess-and-recheck cycle.