Today if a user builds firmware with an incorrect WiFi SSID or password,
they get a generic `WiFi disconnected.` error message.
Extend logging to descirbe the reason that WiFi was disconnected.
I gathered the updated logs for the 3 scenarios below.
```
WiFi: Attempting manual WiFi reconnect...
WiFi: WiFi disconnected (reason=ASSOC_LEAVE). Flagging for reconnect...
WiFi: WiFi disconnected (reason=4WAY_HANDSHAKE_TIMEOUT). Flagging for reconnect...
WiFi: WiFi disconnected (reason=4WAY_HANDSHAKE_TIMEOUT). Flagging for reconnect...
WiFi: WiFi disconnected (reason=4WAY_HANDSHAKE_TIMEOUT). Flagging for reconnect...
```
```
WiFi: WiFi disconnected (reason=NO_AP_FOUND). Flagging for reconnect...
```
```
WiFi: WiFi connected successfully!
WiFi: Got connection
```
Payloads of 166 or 167 bytes previously passed the frame-sized bound
(MAX_CHANNEL_DATA_LENGTH = 167) but were rejected by sendGroupData
against MAX_GROUP_DATA_LENGTH (165), causing ERR_CODE_TABLE_FULL (retry
later) to be returned instead of ERR_CODE_ILLEGAL_ARG.
Fixes#3345
- scope the serial config CLI to RP2040; it was exposing the rescue CLI
(cat/rm/erase) on every ESP32 WiFi build, which gates it behind a
physical long-press
- bound and space out RP2040 rejoins: the core's join busy-waits, so cap
it at 5s and retry every 30s instead of every 10s
- stamp the reconnect timer in setup(), so the first loop() doesn't tear
down an association that is still finishing DHCP
- treat stored credentials as a pair, and pass NULL (not "") for an open
network
- teach build_as_lib.py where SerialWifiInterface moved
arduino-pico's WiFi.begin() blocks for up to 2x its 15s timeout, which
stalled the mesh loop on every reconnect attempt; use beginNoBlock().
Log the IP when the link comes up, and the status code when retrying.
Store ssid/pwd in NodePrefs and set them with 'set wifi.ssid' /
'set wifi.pwd' over USB serial; build-time WIFI_SSID/WIFI_PWD stay as
the fallback. Headless WiFi builds get the config CLI on Serial, which
is otherwise unused there.
SerialWifiInterface has no ESP32-specific code, so move it to
helpers/wifi and reuse it on RP2040. Guard the ESP32-only WiFi
event/auto-reconnect calls and poll link state on RP2040 instead.
The serial command buffers must stay NUL-terminated within their
bounds: if they ever aren't, strlen() can return >= sizeof(command)
and the read loop would index past the buffer. Additionally, a full
buffer now becomes a completed line (end-of-line marker placed
inside the buffer, NUL terminator kept) instead of overwriting the
terminator and silently corrupting the buffer for the next pass.
Applies to the serial CLI readers of the repeater, room server,
sensor and secure chat examples, and to the CLI rescue reader of
the companion example.
ripplebiz