Merge upstream companion-v1.17.0 (CAD) into power-saving

Adopts hardware Channel Activity Detection (wired into
RadioLibWrapper::isChannelActive() alongside our RSSI-threshold check
and RX duty-cycle power-save), MCU temperature telemetry, LR2021
standby workaround, DISPLAY_SCALE/FLIP overrides, NRF52Board
shutdownPeripherals() refactor, and misc upstream fixes.

Declines upstream's ConfigSerializer-based NodePrefs rewrite,
MultiSerialInterface/interface_manager, and UIColor palette system —
each would have broken large parts of the Solo-specific feature set
(NodePrefs fields, per-variant single serial_interface, enum-based
DisplayDriver::Color). Flagged as candidate follow-up migrations, not
permanent no's.

Also fixes several pre-existing bugs surfaced while chasing silent
merge breaks (stale newMsg() override signature in ui-tiny/ui-orig,
dead UIEventType::newContactMessage case, missing ContactsIterator
init), bumps FIRMWARE_VERSION/MESHCORE_VERSION to 1.17, and fixes a
missing <cstdlib> include that broke the native ConfigSerializer unit
tests.

Verified via 13+ pio run builds across ESP32/nRF52, all 3 companion UI
variants, and 7 display drivers, plus the full native unit test suite
(33/33 passing).

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

examples/simple_repeater/main.cpp

@@ -8,6 +8,11 @@
   static UITask ui_task(display);
 #endif
 
+#ifdef ETHERNET_ENABLED
+  #define ETHERNET_CLI_BANNER "MeshCore Repeater CLI"
+  #include <helpers/nrf52/EthernetCLI.h>
+#endif
+
 StdRNG fast_rng;
 SimpleMeshTables tables;
 
@@ -18,6 +23,9 @@ void halt() {
 }
 
 static char command[160];
+#ifdef ETHERNET_ENABLED
+static char ethernet_command[160];
+#endif
 
 // For power saving
 unsigned long POWERSAVING_FIRSTSLEEP_SECS = 120; // The first sleep (if enabled) from boot
@@ -33,6 +41,10 @@ void setup() {
 
   board.begin();
 
+#ifdef HAS_EXTERNAL_WATCHDOG
+  external_watchdog.begin();
+#endif
+
 #if defined(MESH_DEBUG) && defined(NRF52_PLATFORM)
   // give some extra time for serial to settle so
   // boot debug messages can be seen on terminal
@@ -86,6 +98,9 @@ void setup() {
   mesh::Utils::printHex(Serial, the_mesh.self_id.pub_key, PUB_KEY_SIZE); Serial.println();
 
   command[0] = 0;
+#ifdef ETHERNET_ENABLED
+  ethernet_command[0] = 0;
+#endif
 
   sensors.begin();
 
@@ -95,6 +110,10 @@ void setup() {
   ui_task.begin(the_mesh.getNodePrefs(), FIRMWARE_BUILD_DATE, FIRMWARE_VERSION);
 #endif
 
+#ifdef ETHERNET_ENABLED
+  ethernet_start_task();
+#endif
+
   // send out initial zero hop Advertisement to the mesh
 #if ENABLE_ADVERT_ON_BOOT == 1
   the_mesh.sendSelfAdvertisement(16000, false);
@@ -104,6 +123,7 @@ void setup() {
 }
 
 void loop() {
+  // Handle Serial CLI
   int len = strlen(command);
   while (Serial.available() && len < sizeof(command)-1) {
     char c = Serial.read();
@@ -122,7 +142,14 @@ void loop() {
     Serial.print('\n');
     command[len - 1] = 0;  // replace newline with C string null terminator
     char reply[160];
+    reply[0] = 0;
+#ifdef ETHERNET_ENABLED
+    if (!ethernet_handle_command(command, reply)) {
+      the_mesh.handleCommand(0, command, reply);
+    }
+#else
     the_mesh.handleCommand(0, command, reply);  // NOTE: there is no sender_timestamp via serial!
+#endif
     if (reply[0]) {
       Serial.print("  -> "); Serial.println(reply);
     }
@@ -130,7 +157,20 @@ void loop() {
     command[0] = 0;  // reset command buffer
   }
 
-#if defined(PIN_USER_BTN) && defined(_SEEED_SENSECAP_SOLAR_H_)
+#ifdef ETHERNET_ENABLED
+  ethernet_loop_maintain();
+  if (ethernet_read_line(ethernet_command, sizeof(ethernet_command))) {
+    char reply[160];
+    reply[0] = 0;
+    if (!ethernet_handle_command(ethernet_command, reply)) {
+      the_mesh.handleCommand(0, ethernet_command, reply);
+    }
+    ethernet_send_reply(reply);
+    ethernet_command[0] = 0;
+  }
+#endif
+
+#if defined(PIN_USER_BTN) && defined(_SEEED_SENSECAP_SOLAR_H_) && !defined(DISPLAY_CLASS)
   // Hold the user button to power off the SenseCAP Solar repeater.
   int btnState = digitalRead(PIN_USER_BTN);
   if (btnState == LOW) {
@@ -152,6 +192,9 @@ void loop() {
 #endif
   rtc_clock.tick();
 
+#ifdef HAS_EXTERNAL_WATCHDOG
+  external_watchdog.loop();
+#endif
   if (the_mesh.getNodePrefs()->powersaving_enabled && !the_mesh.hasPendingWork()) {
 #if defined(NRF52_PLATFORM)
     board.sleep(0); // nrf ignores seconds param, sleeps whenever possible