Fix SENSOR power saving deep sleep truncating TX and skipping sleep on failed reads (#10939)

* Fix SENSOR power saving deep sleep behavior

Deep sleep could be entered while a telemetry packet was still queued
or on air, truncating the transmission. canSleep() gained a deepSleep
parameter and now vetoes in that case; light sleep is unchanged.
Telemetry modules defer a pending deep sleep (bounded to 30s) until the
radio is idle and no longer let the sensor polling interval override
the 5s pre-sleep grace period. A failed sensor read still arms deep
sleep instead of leaving the node awake for a full telemetry interval.

Fixes #10890
Fixes #10932

* Deduplicate telemetry deep sleep deferral logic

Move the radio-busy deferral and its counter into BaseTelemetryModule
and add an isPowerSavingSensor() helper. Removes the telemetry-specific
counter from OSThread. The sleep arming block stays per module because
it needs protected OSThread members not visible to the base class.

src/modules/Telemetry/PowerTelemetry.cpp

@@ -34,6 +34,8 @@ extern void drawCommonHeader(OLEDDisplay *display, int16_t x, int16_t y, const c
 int32_t PowerTelemetryModule::runOnce()
 {
     if (sleepOnNextExecution == true) {
+        if (shouldDeferDeepSleep())
+            return PREFLIGHT_SLEEP_RETRY_MS;
         sleepOnNextExecution = false;
         uint32_t nightyNightMs = Default::getConfiguredOrDefaultMs(moduleConfig.telemetry.power_update_interval,
                                                                    default_telemetry_broadcast_interval_secs);
@@ -106,6 +108,11 @@ int32_t PowerTelemetryModule::runOnce()
             lastSentToPhone = millis();
         }
     }
+    if (sleepOnNextExecution) {
+        // Honor the pre-sleep grace period armed in sendTelemetry(): OSThread reschedules with
+        // this return value, which would otherwise override setIntervalFromNow()
+        return FIVE_SECONDS_MS;
+    }
     return min(sendToPhoneIntervalMs, sendToMeshIntervalMs);
 }
 
@@ -258,7 +265,8 @@ bool PowerTelemetryModule::sendTelemetry(NodeNum dest, bool phoneOnly)
     meshtastic_Telemetry m = meshtastic_Telemetry_init_zero;
     m.which_variant = meshtastic_Telemetry_power_metrics_tag;
     m.time = getTime();
-    if (getPowerTelemetry(&m)) {
+    bool validTelemetry = getPowerTelemetry(&m);
+    if (validTelemetry) {
         LOG_INFO("Send: ch1_voltage=%f, ch1_current=%f, ch2_voltage=%f, ch2_current=%f, "
                  "ch3_voltage=%f, ch3_current=%f",
                  m.variant.power_metrics.ch1_voltage, m.variant.power_metrics.ch1_current, m.variant.power_metrics.ch2_voltage,
@@ -284,16 +292,21 @@ bool PowerTelemetryModule::sendTelemetry(NodeNum dest, bool phoneOnly)
         } else {
             LOG_INFO("Send packet to mesh");
             service->sendToMesh(p, RX_SRC_LOCAL, true);
-
-            if (config.device.role == meshtastic_Config_DeviceConfig_Role_SENSOR && config.power.is_power_saving) {
-                LOG_DEBUG("Start next execution in 5s then sleep");
-                sleepOnNextExecution = true;
-                setIntervalFromNow(5000);
-            }
         }
-        return true;
     }
-    return false;
+
+    // Arm the pre-sleep sequence even when no valid reading was available this cycle: a
+    // power-saving SENSOR node must still return to deep sleep, otherwise it stays awake
+    // until the next telemetry interval and drains its battery
+    if (!phoneOnly && isPowerSavingSensor()) {
+        if (!validTelemetry)
+            LOG_WARN("Power telemetry unavailable this cycle, sleep without sending");
+        sleepOnNextExecution = true;
+        preflightSleepDeferrals = 0;
+        LOG_DEBUG("Start next execution in 5s then sleep");
+        setIntervalFromNow(FIVE_SECONDS_MS);
+    }
+    return validTelemetry;
 }
 
 #endif