Add race and station management

- races table: name, date, description, is_active
- stations table: ordered checkpoints with GPS per race
- New /api/races and /api/races/{id}/stations endpoints
- Upload now requires race + station selection; uses station GPS
  so images without GPS EXIF are accepted
- passages filtered by active race throughout
- RacePage: create races, manage stations (add/edit/delete checkpoints)
- Navbar shows active race name
- Start and finish stations created automatically per race

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/pages/ReviewPage.jsx

@@ -149,14 +149,17 @@ function ReviewCard({ passage, athletes, onResolved, onDeleted }) {
   )
 }
 
-export default function ReviewPage() {
+export default function ReviewPage({ activeRace }) {
   const [queue, setQueue] = useState([])
   const [athletes, setAthletes] = useState([])
   const [loading, setLoading] = useState(true)
 
   const load = async () => {
     setLoading(true)
-    const [q, a] = await Promise.all([api.getReviewQueue(), api.getAthletes()])
+    const [q, a] = await Promise.all([
+      api.getReviewQueue(activeRace?.race_id),
+      api.getAthletes(),
+    ])
     setQueue(q)
     setAthletes(a)
     setLoading(false)