feat(tesla): collapse OD strip when connected, sync with in-car nav destination

- Server: include active_route_destination (lat/lng/eta) from drive_state.
- When Tesla is connected, the Origin → Destination strip collapses to a
  single ConnectedTripStrip: "From car · Where to?". The origin is implicit
  (the car's GPS), the manual From input + crosshair button disappear.
- If Tesla nav already has a destination, it auto-fills as the trip
  destination; if the user has typed something else, an inline "Use Tesla
  nav" button offers a one-tap swap.
- Mocks: driving + charging scenarios include an activeRoute so the flow
  is testable end-to-end via ?mockTesla=driving / ?mockTesla=charging.

server/routes/tesla.ts

@@ -210,6 +210,21 @@ router.get('/api/tesla/state', requireOwner, async (req, res) => {
       vin: tokens.vin ? `…${tokens.vin.slice(-4)}` : null,
       vehicleName: vs.vehicle_name ?? null,
       softwareVersion: vs.car_version ?? null,
+      // Active in-car nav destination (set in Tesla nav by the driver, or by
+      // our own send-to-nav). Useful as a default trip destination.
+      activeRoute: (typeof ds.active_route_destination === 'string' && ds.active_route_destination)
+        ? {
+            destination: ds.active_route_destination,
+            lat: typeof ds.active_route_latitude === 'number' ? ds.active_route_latitude : null,
+            lng: typeof ds.active_route_longitude === 'number' ? ds.active_route_longitude : null,
+            kmToArrival: typeof ds.active_route_miles_to_arrival === 'number'
+              ? Math.round(ds.active_route_miles_to_arrival * 1.60934) : null,
+            minutesToArrival: typeof ds.active_route_minutes_to_arrival === 'number'
+              ? Math.round(ds.active_route_minutes_to_arrival) : null,
+            trafficMinutesDelay: typeof ds.active_route_traffic_minutes_delay === 'number'
+              ? Math.round(ds.active_route_traffic_minutes_delay) : 0,
+          }
+        : null,
       fetchedAt: Date.now(),
     });
   } catch (err) {