Add opt-in low power Sensor dog tracking

Acquire fresh GPS and validated UTC, check an authenticated owner Companion, and apply saved lost-status cadence with bounded awake windows. Persist request tags, routes, and six-hour flood reservations; preserve the four-day cutoff across sleep and restart.

Keep Dispatcher recovery active after a failed radio wake, honor denied flood retries after lost TxDone, and qualify GPS ownership and clock corrections. Add executable regression tests and nRF52/ESP32 Sensor build jobs.

Validation: six firmware builds, 1829 native test cases, sanitized tracker/storage/GPS/sleep/recovery tests, and strict documentation build. Bluetooth Find My advertising and automatic Room mailbox polling remain separate work.

src/Dispatcher.cpp

@@ -224,6 +224,9 @@ bool Dispatcher::startOutboundTransmit() {
 
 bool Dispatcher::scheduleOutboundRadioRetry() {
   if (outbound == NULL || outbound_radio_retry_used || outbound_cancellation != OutboundCancellation::None) return false;
+  // A lost TxDone may follow a real transmission, so a denied flood must not
+  // spend its reserved airtime again during radio recovery.
+  if (outbound->isRouteFlood() && outbound->flood_retry_policy == FLOOD_RETRY_POLICY_DENY) return false;
 
   outbound_radio_retry_used = true;
   outbound_radio_retry_pending = true;