Add configurable max hops filter for auto-add contacts

Filter auto-add of new contacts by hop count (issues #1533, #1546).
Setting is configurable from the companion app via extended
CMD_SET/GET_AUTOADD_CONFIG protocol (0 = no limit, 1-63 = max hops).

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

examples/companion_radio/DataStore.cpp

@@ -229,6 +229,7 @@ void DataStore::loadPrefsInt(const char *filename, NodePrefs& _prefs, double& no
     file.read((uint8_t *)&_prefs.gps_enabled, sizeof(_prefs.gps_enabled));                 // 85
     file.read((uint8_t *)&_prefs.gps_interval, sizeof(_prefs.gps_interval));               // 86
     file.read((uint8_t *)&_prefs.autoadd_config, sizeof(_prefs.autoadd_config));           // 87
+    file.read((uint8_t *)&_prefs.autoadd_max_hops, sizeof(_prefs.autoadd_max_hops));       // 88
 
     file.close();
   }
@@ -265,6 +266,7 @@ void DataStore::savePrefs(const NodePrefs& _prefs, double node_lat, double node_
     file.write((uint8_t *)&_prefs.gps_enabled, sizeof(_prefs.gps_enabled));                 // 85
     file.write((uint8_t *)&_prefs.gps_interval, sizeof(_prefs.gps_interval));               // 86
     file.write((uint8_t *)&_prefs.autoadd_config, sizeof(_prefs.autoadd_config));           // 87
+    file.write((uint8_t *)&_prefs.autoadd_max_hops, sizeof(_prefs.autoadd_max_hops));      // 88
 
     file.close();
   }