feat(history): show reverse-geocoded location during trip scrubbing

- Location name (road + city) appears below time/speed in the timeline panel
- Debounced 600ms so dragging the scrubber doesn't spam Nominatim
- Deduped by ~3 decimal lat/lon so stationary replay doesn't re-fetch
- Cleared when a new trip is loaded

Co-authored-by: Copilot <[email protected]>

static/js/history.js

@@ -22,6 +22,34 @@
     let replayTimer = null;
     let replayController = null;
     const recenterBtn = document.getElementById("btn-recenter-history");
+    const replayLocation = document.getElementById("trip-replay-location");
+
+    let _geoTimer = null;
+    let _lastGeoKey = null;
+
+    function geocodePoint(lat, lon) {
+        const key = `${lat.toFixed(3)},${lon.toFixed(3)}`;
+        if (key === _lastGeoKey) return;
+        _lastGeoKey = key;
+        fetch(`https://nominatim.openstreetmap.org/reverse?format=jsonv2&lat=${lat}&lon=${lon}`, {
+            headers: { 'Accept-Language': 'en' }
+        })
+        .then(r => r.ok ? r.json() : null)
+        .then(data => {
+            if (!data) return;
+            const a = data.address || {};
+            const road = a.road || a.hamlet || a.village || a.suburb || '';
+            const city = a.city || a.town || a.village || a.municipality || '';
+            replayLocation.textContent = [road, city].filter(Boolean).join(', ')
+                || data.display_name?.split(',').slice(0, 2).join(',') || '';
+        })
+        .catch(() => {});
+    }
+
+    function scheduleGeocode(lat, lon) {
+        clearTimeout(_geoTimer);
+        _geoTimer = setTimeout(() => geocodePoint(lat, lon), 600);
+    }
 
     function formatDuration(seconds) {
         const hours = Math.floor(seconds / 3600);
@@ -69,6 +97,7 @@
         replayTime.textContent = formatDate(point.datetime);
         const source = point.speed_source === "obd" ? "OBD wheel" : "GPS";
         replaySpeed.textContent = `${source} speed: ${formatSpeed(point.speed)}`;
+        scheduleGeocode(point.latitude, point.longitude);
     }
 
     function initializeTimeline(points) {
@@ -77,6 +106,8 @@
         scrubber.max = Math.max(0, points.length - 1);
         scrubber.value = 0;
         timeline.hidden = points.length === 0;
+        replayLocation.textContent = '';
+        _lastGeoKey = null;
         if (vehicleMarker) {
             vehicleMarker.remove();
         }