Add runtime UV protection toggle and treat near-zero sense as external power.

Per-pod NVS enable (default off) via UART/ESP-NOW/dashboard, and skip UV latch when LiPo ADC reads ~0 mV so USB/external supply still boots.

Co-authored-by: Cursor <cursoragent@cursor.com>

main/battery_uv.c

@@ -19,15 +19,55 @@ static uint8_t s_charge_streak;
 
 bool battery_uv_is_latched(void) { return pod_settings_is_uv_latched(); }
 
+static bool channel_is_absent(uint32_t mv) {
+  return mv < BATTERY_UV_ABSENT_ADC_MV;
+}
+
+static bool channel_is_under(uint32_t mv) {
+  return !channel_is_absent(mv) && mv < BATTERY_UV_ADC_MV;
+}
+
+static void log_lipo_reading(const char *ctx, const board_lipo_reading_t *reading) {
+  if (reading == NULL) {
+    return;
+  }
+  ESP_LOGI(TAG,
+           "%s LIPO1 %s %lu mV  LIPO2 %s %lu mV", ctx,
+           reading->lipo1_valid ? "ok" : "n/a",
+           (unsigned long)reading->lipo1_mv, reading->lipo2_valid ? "ok" : "n/a",
+           (unsigned long)reading->lipo2_mv);
+}
+
+bool battery_uv_reading_is_external(const board_lipo_reading_t *reading) {
+  if (reading == NULL) {
+    return false;
+  }
+
+  bool any_valid = false;
+  if (reading->lipo1_valid) {
+    any_valid = true;
+    if (!channel_is_absent(reading->lipo1_mv)) {
+      return false;
+    }
+  }
+  if (reading->lipo2_valid) {
+    any_valid = true;
+    if (!channel_is_absent(reading->lipo2_mv)) {
+      return false;
+    }
+  }
+  return any_valid;
+}
+
 bool battery_uv_reading_is_under(const board_lipo_reading_t *reading) {
   if (reading == NULL) {
     return false;
   }
 
-  if (reading->lipo1_valid && reading->lipo1_mv < BATTERY_UV_ADC_MV) {
+  if (reading->lipo1_valid && channel_is_under(reading->lipo1_mv)) {
     return true;
   }
-  if (reading->lipo2_valid && reading->lipo2_mv < BATTERY_UV_ADC_MV) {
+  if (reading->lipo2_valid && channel_is_under(reading->lipo2_mv)) {
     return true;
   }
   return false;
@@ -38,25 +78,39 @@ bool battery_uv_reading_is_charged(const board_lipo_reading_t *reading) {
     return false;
   }
 
-  bool any_valid = false;
-  if (reading->lipo1_valid) {
-    any_valid = true;
+  bool any_pack = false;
+  if (reading->lipo1_valid && !channel_is_absent(reading->lipo1_mv)) {
+    any_pack = true;
     if (reading->lipo1_mv < BATTERY_CHARGE_ADC_MV) {
       return false;
     }
   }
-  if (reading->lipo2_valid) {
-    any_valid = true;
+  if (reading->lipo2_valid && !channel_is_absent(reading->lipo2_mv)) {
+    any_pack = true;
     if (reading->lipo2_mv < BATTERY_CHARGE_ADC_MV) {
       return false;
     }
   }
-  return any_valid;
+  return any_pack;
 }
 
 bool battery_uv_evaluate_boot(void) {
+  if (!pod_settings_is_uv_enabled()) {
+    ESP_LOGI(TAG, "UV protection disabled — normal boot");
+    return false;
+  }
+
   board_lipo_reading_t reading;
   board_input_read_lipo(&reading);
+  log_lipo_reading("boot check", &reading);
+
+  if (battery_uv_reading_is_external(&reading)) {
+    ESP_LOGI(TAG, "near-zero LiPo sense — external supply, normal boot");
+    if (pod_settings_is_uv_latched()) {
+      pod_settings_clear_uv_latched();
+    }
+    return false;
+  }
 
   if (pod_settings_is_uv_latched() && battery_uv_reading_is_charged(&reading)) {
     ESP_LOGI(TAG, "charged — clearing UV latch");
@@ -78,12 +132,19 @@ bool battery_uv_evaluate_boot(void) {
 }
 
 void battery_uv_poll(const board_lipo_reading_t *reading) {
-  if (reading == NULL || pod_settings_is_uv_latched()) {
+  if (reading == NULL || !pod_settings_is_uv_enabled() ||
+      pod_settings_is_uv_latched()) {
+    return;
+  }
+
+  if (battery_uv_reading_is_external(reading)) {
+    s_uv_streak = 0;
     return;
   }
 
   if (battery_uv_reading_is_under(reading)) {
     s_uv_streak++;
+    log_lipo_reading("under-voltage", reading);
     ESP_LOGW(TAG, "under-voltage sample %u/%u", (unsigned)s_uv_streak,
              (unsigned)UV_DEBOUNCE_SAMPLES);
     if (s_uv_streak >= UV_DEBOUNCE_SAMPLES) {
@@ -109,8 +170,13 @@ void battery_uv_run_mode(void) {
   while (1) {
     board_lipo_reading_t reading;
     board_input_read_lipo(&reading);
+    log_lipo_reading("energy-save", &reading);
 
-    if (battery_uv_reading_is_charged(&reading)) {
+    if (battery_uv_reading_is_external(&reading)) {
+      ESP_LOGI(TAG, "external supply — clearing UV latch and restarting");
+      pod_settings_clear_uv_latched();
+      pod_schedule_restart();
+    } else if (battery_uv_reading_is_charged(&reading)) {
       s_charge_streak++;
       ESP_LOGI(TAG, "charge sample %u/%u", (unsigned)s_charge_streak,
                (unsigned)UV_DEBOUNCE_SAMPLES);