feat: odometer in trips/overview, trips upload toggle, fix video count

- OBD odometer now logged to tracking rows on every GPS snapshot
- trips table: START_ODOMETER/END_ODOMETER columns (migration)
- build_trip_summaries: picks odometer from first/last tracking row
- list_trips: uses real OBD odo, falls back to cumulative distance
- overview stats: odometer_km (max seen from OBD), video_count fixed
- history page: Odometer column shows start→end km per trip
- app_upload: TRIPS_UPLOAD_SETTING_KEY, is_trips_upload_enabled()
- _upload_tracking_batch: skips when trips upload is off
- settings: separate 'Upload trips & GPS' toggle from dashcam toggle

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

templates/index.html

@@ -136,6 +136,10 @@
                         <div class="text-xs text-muted fw-bold text-uppercase mb-1">Top speed ever</div>
                         <div class="fw-bold fs-5 text-dark" id="stat-topspeed">—</div>
                     </div>
+                    <div class="col-6 col-lg-12">
+                        <div class="text-xs text-muted fw-bold text-uppercase mb-1">Odometer</div>
+                        <div class="fw-bold fs-5 text-dark" id="stat-odometer">—</div>
+                    </div>
                     <div class="col-6 col-lg-12">
                         <div class="text-xs text-muted fw-bold text-uppercase mb-1">Videos on Pi</div>
                         <div class="fw-bold fs-5 text-dark" id="stat-videos">—</div>
@@ -218,6 +222,7 @@
             document.getElementById('stat-km').textContent = d.total_km.toFixed(1) + ' km';
             document.getElementById('stat-time').textContent = d.total_duration_s > 0 ? fmtDuration(d.total_duration_s) : '—';
             document.getElementById('stat-topspeed').textContent = d.all_time_max_speed > 0 ? d.all_time_max_speed + ' km/h' : '—';
+            document.getElementById('stat-odometer').textContent = d.odometer_km != null ? Math.round(d.odometer_km).toLocaleString() + ' km' : '—';
             document.getElementById('stat-videos').textContent = d.video_count;
             const dtcEl = document.getElementById('stat-dtc');
             dtcEl.textContent = d.active_dtc;