Support fully direct request/responses (#9455)

Co-authored-by: Ben Meadors <benmmeadors@gmail.com>

src/mesh/Router.cpp

@@ -266,6 +266,13 @@ ErrorCode Router::sendLocal(meshtastic_MeshPacket *p, RxSource src)
             }
         }
 
+        // If someone asks for acks on broadcast, we need the hop limit to be at least one, so that first node that receives our
+        // message will rebroadcast.  But asking for hop_limit 0 in that context means the client app has no preference on hop
+        // counts and we want this message to get through the whole mesh, so use the default.
+        if (src == RX_SRC_USER && p->want_ack && p->hop_limit == 0) {
+            p->hop_limit = Default::getConfiguredOrDefaultHopLimit(config.lora.hop_limit);
+        }
+
         return send(p);
     }
 }