v1.13.0

• Draw a trail on the radar from positions collected while the same
  callsign is selected
• Show today's traffic on the waiting board
• List other aircraft in range on an ALSO line under NEXT
• Toggle type silhouettes, optional FR24 aircraft photos, and auto
  night (follow sun.sun, split-flap stays mechanical)
• Filter airliners-only, hide helicopters, hide military types, and
  set a minimum ground speed
• Skip the current aircraft for five minutes, or pin it while it stays
  in range (flightwall.skip / pin / unpin plus buttons)
• Mirror the TV PNG on the Flightwall dashboard via camera.flightwall_board
• Keep writing /local/flightwall-board.png even when the TV is off
• Add scripts/release.sh to tag and publish a GitHub release