A BRIDGES scan can legitimately list the same MASTER on both TS1 and
TS2 for one TG (e.g. an inject-only proxy whose connected hotspots
collectively use both slots). SubscriptionRouter.resolve() kept both
as distinct legs, so dmrd_received called send_to_system twice for
that MASTER per source frame.
Legacy's dumb send_peers() broadcast made that harmless: each
hotspot's own radio silently dropped the slot it didn't want. This
server's send_peers() instead resolves every peer's real listen slot
from its own OPTIONS regardless of the wire slot
(iter_downlink_voice_slots), so the second leg delivered the same
audio a second time to every subscribed peer - doubling the downlink
rate and making unpaced bridges (e.g. ysf2dmr) sound slow. Only
OBP-sourced calls hit this: a MASTER never forwards to itself, so
locally-originated (HBP) calls never produced a redundant leg.
Collapse forward legs to a MASTER/PEER target down to one per
(target_system, target_tgid), keeping distinct legs for OpenBridge
targets and for legitimate TG-translation legs to the same target on
a different TGID.