Three fork-introduced dependencies had leaked into non-ESP32 builds, breaking
every nRF52 and RP2040 target since 7e4f75c9 (2026-04-10):
- The `memory` CLI command called ESP.getFreeHeap()/heap_caps_* unguarded from
shared CommonCLI.cpp. ESP32 output is unchanged; other platforms now report
newlib arena stats, omitting min-ever-free and largest-free-block rather than
substituting numbers that mean something different.
- The vendored PsychicMqttClient (ESP-IDF esp-mqtt) was pulled in by the LDF on
nRF52; nrf52_base now lib_ignores it, matching how RP2040 variants ignore BLE.
- JWTHelper.cpp and MQTTMessageBuilder.cpp are excluded in arduino_base, but 22
variants re-glob helpers/*.cpp after inheriting it, which undoes the exclusion.
Guarding the file contents on WITH_MQTT_BRIDGE is robust against any variant's
filter, and matches helpers/esp32/WebConfigServer.cpp.
Verified: RAK4631 repeater + room server, Heltec T114, T1000-E, Wio WM1110,
Xiao nRF52 and ThinkNode M1 all build. ESP32 observer builds are byte-identical
to before (RAM and flash), and the native suite stays at 267/267.
RP2040 still fails separately: four boards declare the pre-force_ap
startOTAUpdate signature. Not addressed here.