Both Clyde North observers sat WL_CONNECTED on an AP that kept beaconing
after its bridge to the wired LAN died: association up, good RSSI, stale
DHCP lease, but ARP-invisible and both MQTT brokers stuck in backoff.
The firmware equated "associated" with "online", so neither node ever
re-scanned and the outage held until a manual reassociation.
Add a connectivity watchdog to NetworkService: while connected, ARP-probe
the gateway every 30s (posted to the lwIP tcpip thread, safe on both the
IDF4 and IDF5 cores). If the gateway stays silent for 3 minutes, clear
the channel hint and force a full disconnect/rescan so the node can roam
to a healthy AP, backing off exponentially (up to 48min) while the
outage persists. Nodes without a gateway skip the probe.
Add a `wifi reconnect` repeater command that triggers the same forced
reassociation on demand, and report `gw:ok|lost wd:<count>` in
`get wifi.status`. Teach the web panel parser the new fields (also fixes
the IP metric rendering as "x.x.x.x channel:n") and show Gateway and
Channel in the Wi-Fi card.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
