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/companion_radio/MyMesh.h

@@ -12,12 +12,12 @@ class UITask;
 #define FIRMWARE_VER_CODE 13
 
 #ifndef FIRMWARE_BUILD_DATE
-#define FIRMWARE_BUILD_DATE "6 Jun 2026"
+#define FIRMWARE_BUILD_DATE "11 Aug 2026"
 #endif
 
 // Versioning: vX.Y = upstream base, solo.N = fork revision
 #ifndef FIRMWARE_VERSION
-#define FIRMWARE_VERSION "v1.16-solo.0"
+#define FIRMWARE_VERSION "v1.17-solo.0"
 #endif
 
 #if defined(NRF52_PLATFORM) || defined(STM32_PLATFORM)
@@ -140,6 +140,7 @@ public:
 protected:
   float getAirtimeBudgetFactor() const override;
   int getInterferenceThreshold() const override;
+  bool getCADEnabled() const override;
   int calcRxDelay(float score, uint32_t air_time) const override;
   uint32_t getRetransmitDelay(const mesh::Packet *packet) override;
   uint32_t getDirectRetransmitDelay(const mesh::Packet *packet) override;
@@ -304,7 +305,6 @@ public:
     return false;
   }
 
-
 #if ENV_INCLUDE_GPS == 1
   void applyGpsPrefs() {
     sensors.setSettingValue("gps", _prefs.gps_enabled ? "1" : "0");