fix: stop unit calls to 4000 from being broadcast to every peer

TG/ID 4000 is the dynamic-TG reset control code and can never appear in
_SUB_MAP, so the unknown-destination fallback in _pvt_repeat_targets treated
it as a private call to an unlocated radio and blasted it to every connected
peer. That fallback runs before dmrd_received's own dst_id == 4000 guard, so
the control code has to be filtered at the targeting step too.

src/adn_server/infrastructure/twisted_adapters/udp_hbp.py

@@ -436,12 +436,22 @@ class HBPProtocol(DatagramProtocol):
         to blast the call to peers it can't possibly be for. Returns a
         1-tuple with the exact peer_id when it's still connected here.
 
+        TG/ID 4000 is the dynamic-TG reset control code (see
+        ``_handle_tg4000_packet``/``routing_use_cases.dmrd_received``), never
+        a real subscriber -- it can never appear in _SUB_MAP, so it would
+        otherwise always fall into the "unknown destination" broadcast
+        fallback above and get blasted to every peer. That fallback runs
+        before dmrd_received's own dst_id == 4000 guard ever sees the
+        packet, so it must be special-cased here too.
+
         The report_slot / "SYSTEM-N" monitor display name is NOT used for
         this — it's cosmetic and can be reassigned to a different peer across
         refreshes (self-service peers without a stable report_slot fall back
         to a sorted-by-id allocation recomputed each time). The raw peer_id
         is what's actually stable.
         """
+        if int_id(dst_id) == 4000:
+            return ()
         sub_map = self._CONFIG.get("_SUB_MAP")
         if not sub_map:
             return None

tests/infrastructure/test_hbp_private_call_targeting.py

@@ -31,6 +31,8 @@ parity) -- see test_hbp_repeat_private_call.py."""
 
 from __future__ import annotations
 
+import dataclasses
+
 from tests.harness.deterministic import DeterministicScenario, PacketSpec
 from tests.support.hbp_repeat_stack import build_hbp_repeat_stack
 
@@ -110,6 +112,24 @@ def test_private_call_not_delivered_locally_when_known_on_different_system() ->
     assert not stack.transport.for_addr(_ADDR_OTHER), "destination known elsewhere must not repeat locally"
 
 
+def test_private_call_to_4000_not_broadcast() -> None:
+    """TG/ID 4000 is the dynamic-TG reset control code, never a real subscriber --
+    it can never appear in _SUB_MAP, so without a special case it always fell into
+    the "unknown destination" broadcast fallback and reached every connected peer
+    instead of being stopped at the server (dmrd_received's own dst_id == 4000
+    guard runs too late: _pvt_repeat_targets/the REPEAT loop already ran)."""
+    stack = build_hbp_repeat_stack(talker_alias=True)
+    stack.register_peer(_PEER_TX, _ADDR_TX, options="TS2=7304;")
+    stack.register_peer(_PEER_RX, _ADDR_RX, options="TS2=7304;")
+    stack.register_peer(_PEER_OTHER, _ADDR_OTHER, options="TS2=7304;")
+
+    base = dataclasses.replace(_private_spec(), dst_id=4000)
+    _fire_private_call(stack, base)
+
+    assert not stack.transport.for_addr(_ADDR_RX), "TG 4000 must not be broadcast to any peer"
+    assert not stack.transport.for_addr(_ADDR_OTHER), "TG 4000 must not be broadcast to any peer"
+
+
 def test_sub_map_entries_for_peer_purged_on_reconnect() -> None:
     """Once a hotspot finishes (re)logging in, any SUB_MAP entry pointing at it is
     stale -- the radio may have moved to a different hotspot while this one was