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>

platformio.ini

@@ -19,7 +19,8 @@ monitor_speed = 115200
 lib_deps =
   SPI
   Wire
-  jgromes/RadioLib @ ^7.6.0
+  ;jgromes/RadioLib @ ^7.7.1
+  https://github.com/jgromes/RadioLib.git#6d8934836678d8894e3d556550475b37dce3e2b6
   rweather/Crypto @ ^0.4.0
   adafruit/RTClib @ ^2.1.3
   melopero/Melopero RV3028 @ ^1.1.0
@@ -92,16 +93,17 @@ build_flags = ${arduino_base.build_flags}
   -D NRF52_PLATFORM
   -D LFS_NO_ASSERT=1
   -D EXTRAFS=1
+  -D USE_CC310_HW_CRYPTO=1
 lib_deps =
   ${arduino_base.lib_deps}
-  https://github.com/oltaco/CustomLFS#0.2.2
+  https://github.com/oltaco/CustomLFS#0.2.3
 ; ----------------- RP2040 ---------------------
 
 [rp2040_base]
 extends = arduino_base
 upload_protocol = picotool
 board_build.core = earlephilhower
-platform = https://github.com/maxgerhardt/platform-raspberrypi.git#4e22a0d ; framework-arduinopico @ 1.50600.0+sha.6a1d13e9
+platform = https://github.com/maxgerhardt/platform-raspberrypi.git   ; framework-arduinopico @ 1.50600.0+sha.6a1d13e9
 build_flags = ${arduino_base.build_flags}
   -D RP2040_PLATFORM
 
@@ -164,9 +166,26 @@ build_flags = -std=c++17
   -I src
   -I test/mocks
 test_build_src = yes
+test_ignore = test_kiss_modem
 build_src_filter =
   -<*>
   +<../src/Utils.cpp>
   +<../src/Packet.cpp>
+  +<../src/helpers/ConfigSerializer.cpp>
+lib_deps =
+  google/googletest @ 1.17.0
+
+[env:native_kiss_modem]
+platform = native
+test_framework = googletest
+build_flags = -std=c++17
+  -I test/mocks
+  -I src
+  -I examples/kiss_modem
+test_build_src = yes
+test_filter = test_kiss_modem
+build_src_filter =
+  -<*>
+  +<../examples/kiss_modem/KissModem.cpp>
 lib_deps =
   google/googletest @ 1.17.0