Merge remote-tracking branch 'upstream/dev' into integrate-upstream-dev-2026-08-09

Integrates upstream v1.17.0. Key adaptations:
- companion + repeater NodePrefs moved to upstream's new ConfigSerializer
  (prefs.json) format; EastMesh fields (companion wifi, repeater fan and
  MQTT bridge peer) appended as serializer groups/keys
- legacy binary prefs loaders retain EastMesh tail fields, so existing
  devices migrate their settings to the new format
- companion main.cpp adopts upstream InterfaceManager while keeping
  runtime WiFi credentials from prefs
- kept EastMesh release-tag versioning in setup-build-environment action

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

examples/simple_sensor/SensorMesh.cpp

@@ -710,7 +710,6 @@ SensorMesh::SensorMesh(mesh::MainBoard& board, mesh::Radio& radio, mesh::Millise
   set_radio_at = revert_radio_at = 0;
 
   // defaults
-  memset(&_prefs, 0, sizeof(_prefs));
   _prefs.airtime_factor = 1.0;
   _prefs.rx_delay_base =   0.0f;  // turn off by default, was 10.0;
   _prefs.tx_delay_factor = 0.5f;   // was 0.25f