Replace 0xFFFFFFFF sentinel with explicit getOutboundTotal()

Instead of overloading getOutboundCount() with a magic sentinel value,
add a dedicated getOutboundTotal() method to the PacketManager interface
that returns the total queue size without time filtering.

This eliminates the fragile convention that caused the regression and
makes the two operations — time-filtered count vs total count —
explicitly separate in the API.

src/helpers/StaticPoolPacketManager.cpp

@@ -9,7 +9,6 @@ PacketQueue::PacketQueue(int max_entries) {
 }
 
 int PacketQueue::countBefore(uint32_t now) const {
-  if (now == 0xFFFFFFFF) return _num;  // sentinel: count all entries regardless of schedule
   int n = 0;
   for (int j = 0; j < _num; j++) {
     if ((int32_t)(_schedule_table[j] - now) > 0) continue;   // scheduled for future... ignore for now
@@ -98,6 +97,10 @@ int  StaticPoolPacketManager::getOutboundCount(uint32_t now) const {
   return send_queue.countBefore(now);
 }
 
+int  StaticPoolPacketManager::getOutboundTotal() const {
+  return send_queue.count();
+}
+
 int StaticPoolPacketManager::getFreeCount() const {
   return unused.count();
 }