Add timesync burst handling and sender-only timeout

- Add TimeSync fault code and labels in UI/SD/web docs
- Trigger receiver beacon bursts on sender drift, but keep errors sender-local
- Sender flags TimeSync only after TIME_SYNC_ERROR_TIMEOUT_MS

src/sd_logger.cpp

@@ -15,6 +15,8 @@ static const char *fault_text(FaultType fault) {
       return "decode";
     case FaultType::LoraTx:
       return "loratx";
+    case FaultType::TimeSync:
+      return "timesync";
     default:
       return "";
   }