add passenger telemetry

backend/src/services/liveVehicleMapper.js

@@ -0,0 +1,32 @@
+function parseNullableNumber(value) {
+  if (value === undefined || value === null || value === '') {
+    return null;
+  }
+
+  const parsed = Number.parseFloat(value);
+  return Number.isFinite(parsed) ? parsed : null;
+}
+
+function decorateOfficialVehicle(row) {
+  return {
+    ...row,
+    source: 'official',
+    confidence: 1,
+    accuracy_m: parseNullableNumber(row.accuracy_meters),
+    is_estimated: false
+  };
+}
+
+function sortLiveVehicles(a, b) {
+  if (a.source !== b.source) {
+    return a.source === 'official' ? -1 : 1;
+  }
+
+  return new Date(b.last_seen_at).getTime() - new Date(a.last_seen_at).getTime();
+}
+
+module.exports = {
+  decorateOfficialVehicle,
+  parseNullableNumber,
+  sortLiveVehicles
+};