Fix TCP receive: path table update + interface naming + 10Mbps bitrate

- Fix path table insert bug: C++ map::insert() silently fails when key
  exists (unlike Python dict[key]=value). Changed to erase()+insert() so
  updated paths (e.g. local TCP replacing stale LoRa) actually take effect.
- Add name parameter to TcpInterface constructor to give each instance a
  unique identity hash, fixing map collision between backbone and local
  TCP server interfaces.
- Set TCP interface bitrate to 10 Mbps (was 500 bps) so Transport
  correctly prefers TCP paths over LoRa when both exist.
- Add PRG button hold >5s white screen indicator for config portal.
- Boundary mode cull_path_table: evict backbone paths first, preserving
  local paths needed for inbound routing.

Display.h

@@ -1196,7 +1196,14 @@ bool epd_blanked = false;
   }
 #endif
 
+#ifdef BOUNDARY_MODE
+extern bool display_lock_white;
+#endif
+
 void update_display(bool blank = false) {
+  #ifdef BOUNDARY_MODE
+  if (display_lock_white) return;
+  #endif
   display_updating = true;
   if (blank == true) {
     last_disp_update = millis()-disp_update_interval-1;