feat: add periodic auto-advert with GPS position (Auto-Advert tool)

Adds configurable periodic 0-hop self-advert that includes GPS coordinates,
making the device's position visible in other nodes' Nearby Nodes screen.
Options: off / 1min / 2min / 5min / 10min / 30min / 1h.

Accessible via Tools → Auto-Advert. Timer runs in MyMesh::loop().

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

examples/companion_radio/ui-new/UITask.cpp

@@ -1594,6 +1594,7 @@ public:
 #include "BotScreen.h"
 #include "NearbyScreen.h"
 #include "DashboardConfigScreen.h"
+#include "AutoAdvertScreen.h"
 #include "ToolsScreen.h"
 
 // ── HomeScreen ────────────────────────────────────────────────────────────────
@@ -2252,6 +2253,7 @@ void UITask::begin(DisplayDriver* display, SensorManager* sensors, NodePrefs* no
   bot_screen    = new BotScreen(this, node_prefs);
   nearby_screen = new NearbyScreen(this);
   dashboard_config = new DashboardConfigScreen(this, node_prefs);
+  auto_advert_screen = new AutoAdvertScreen(this, node_prefs);
   setCurrScreen(splash);
 
   applyBrightness();
@@ -2286,6 +2288,11 @@ void UITask::gotoDashboardConfig() {
   setCurrScreen(dashboard_config);
 }
 
+void UITask::gotoAutoAdvertScreen() {
+  ((AutoAdvertScreen*)auto_advert_screen)->enter();
+  setCurrScreen(auto_advert_screen);
+}
+
 void UITask::playMelody(const char* melody) {
 #ifdef PIN_BUZZER
   buzzer.playForced(melody);