Add Reticulum destination hash indicator at the top of the captive-portal
config page so users can identify the device.
- Store the 32-char hex destination hash in RTC_NOINIT memory after RNS
starts on a normal boot (survives software reboots into config mode)
- BoundaryConfig.h reads the RTC value and renders a styled hash box at
the top of the HTML page, above the config form
- Falls back to a friendly placeholder if the device has never completed
a normal boot (hash not yet assigned)
- Rebuild precompiled firmware for Heltec V3 and V4 boundary variants
MODE_ACCESS_POINT unconditionally blocks announce broadcasts in
Transport::outbound(), preventing local TCP clients from discovering
each other. Changing to MODE_GATEWAY allows announces to flow through
send_outgoing() which broadcasts to all connected clients.
Root cause: receiver's announce was stored in announce_table but never
rebroadcast on LocalTcpInterface, so sender could never find a path.
