Add opt-in battery alert flood text

src/helpers/CommonCLI.cpp

@@ -556,6 +556,9 @@ void CommonCLI::loadPrefsInt(FILESYSTEM* fs, const char* filename) {
                                sizeof(_prefs->direct_retry_cr7_snr_x4));                        // 662
     retry_cr_read += file.read((uint8_t *)&_prefs->direct_retry_cr8_snr_x4,
                                sizeof(_prefs->direct_retry_cr8_snr_x4));                        // 663
+    _prefs->battery_alert_enabled = 0;
+    size_t battery_alert_read = file.read((uint8_t *)&_prefs->battery_alert_enabled,
+                                          sizeof(_prefs->battery_alert_enabled));                // 664
     // PowerSaving-only prefs stored radio_fem_rxgain at 291, before direct retry timing existed.
     if (radio_fem_rxgain_read != sizeof(_prefs->radio_fem_rxgain)
         && legacy_retry_attempts_read == sizeof(legacy_retry_attempts_or_radio_fem_rxgain)
@@ -654,6 +657,11 @@ void CommonCLI::loadPrefsInt(FILESYSTEM* fs, const char* filename) {
     } else {
       sanitizeDirectRetryCrThresholds(_prefs);
     }
+    if (battery_alert_read != sizeof(_prefs->battery_alert_enabled)) {
+      _prefs->battery_alert_enabled = 0;
+    } else {
+      _prefs->battery_alert_enabled = constrain(_prefs->battery_alert_enabled, 0, 1);
+    }
 
     file.close();
   }
@@ -739,7 +747,8 @@ void CommonCLI::savePrefs(FILESYSTEM* fs) {
     file.write((uint8_t *)&_prefs->direct_retry_cr5_snr_x4, sizeof(_prefs->direct_retry_cr5_snr_x4)); // 661
     file.write((uint8_t *)&_prefs->direct_retry_cr7_snr_x4, sizeof(_prefs->direct_retry_cr7_snr_x4)); // 662
     file.write((uint8_t *)&_prefs->direct_retry_cr8_snr_x4, sizeof(_prefs->direct_retry_cr8_snr_x4)); // 663
-    // next: 664
+    file.write((uint8_t *)&_prefs->battery_alert_enabled, sizeof(_prefs->battery_alert_enabled)); // 664
+    // next: 665
 
     file.close();
   }

src/helpers/CommonCLI.h

@@ -132,6 +132,7 @@ struct NodePrefs { // persisted to file
   int8_t direct_retry_cr5_snr_x4;
   int8_t direct_retry_cr7_snr_x4;
   int8_t direct_retry_cr8_snr_x4;
+  uint8_t battery_alert_enabled;
 };
 
 class CommonCLICallbacks {