feat: ingestion automatique toutes les 6h + indicateur fraîcheur UI

- Symfony Scheduler (MainSchedule) : cron 0,6,12,18h UTC
- IngestionScheduleMessage + IngestionScheduleHandler : pipeline complet
  ingestion → forecasts → impact scores pour toutes les zones Antilles
- messenger.yaml : transport scheduler_main + async Redis (rs971_async)
- entrypoint.sh : 2 workers en background (scheduler_main + async)
- GET /api/status : date/heure de la dernière observation
- SargassesMap : badge "Données du JJ/MM à HH:MM" en bas à gauche

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

frontend/src/api/client.js

@@ -40,6 +40,9 @@ export const api = {
   feedback: {
     create: (data) => post('/feedback', data),
   },
+  status: {
+    get: () => get('/status'),
+  },
   push: {
     vapidKey:    ()     => get('/push/vapid-public-key'),
     subscribe:   (data) => post('/push/subscribe', data),

frontend/src/components/Map/SargassesMap.css

@@ -1,3 +1,18 @@
+/* ── Indicateur fraîcheur données ── */
+.smap-freshness {
+  position: absolute;
+  bottom: 28px;
+  left: 10px;
+  background: rgba(255, 255, 255, 0.82);
+  backdrop-filter: blur(4px);
+  border-radius: 6px;
+  padding: 4px 10px;
+  font-size: 11px;
+  color: #555;
+  pointer-events: none;
+  z-index: 10;
+}
+
 /* ── Spot markers ── */
 .smap-marker {
   cursor: pointer;

frontend/src/components/Map/SargassesMap.jsx

@@ -156,6 +156,18 @@ export default function SargassesMap({ onSpotSelect, selectedSpotId, activeStep,
   const [viewState,    setViewState]    = useState(INITIAL_VIEW);
   const [layerOpacity, setLayerOpacity] = useState(1);
   const [mapStyle,     setMapStyle]     = useState(FALLBACK_STYLE);
+  const [dataDate,     setDataDate]     = useState(null);
+
+  // Fraîcheur des données
+  useEffect(() => {
+    api.status.get()
+      .then(s => {
+        if (s.lastObservation?.detectedAt) {
+          setDataDate(new Date(s.lastObservation.detectedAt));
+        }
+      })
+      .catch(() => {});
+  }, []);
 
   // Load cartoon map style
   useEffect(() => {
@@ -254,6 +266,14 @@ export default function SargassesMap({ onSpotSelect, selectedSpotId, activeStep,
     >
       <NavigationControl position="bottom-right" />
 
+      {dataDate && (
+        <div className="smap-freshness">
+          Données du {dataDate.toLocaleDateString('fr-FR', { day: '2-digit', month: '2-digit' })}
+          {' à '}
+          {dataDate.toLocaleTimeString('fr-FR', { hour: '2-digit', minute: '2-digit' })}
+        </div>
+      )}
+
       {obsGeoJSON && (
         <Source id="observations" type="geojson" data={obsGeoJSON}>
           <Layer {...OBS_STYLES.fill} />