Phase 1 : endpoints API complets

- CoastalPoint → shortName Spot → /api/spots (API Platform)
- SargassumForecast → shortName Forecast → /api/forecasts
- ObservationController : GET /api/observations avec filtres
  bbox (PostGIS ST_Intersects), date, source + geometry ST_AsGeoJSON
- SpotScoreController : GET /api/spots/{id}/score avec ?at= optionnel
- FeedbackController : POST /api/feedback, anonyme, fingerprint SHA256
- CORS : autorisation radarsargasses971.com + localhost dev

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

backend/src/Entity/SargassumObservation.php

@@ -2,9 +2,6 @@
 
 namespace App\Entity;
 
-use ApiPlatform\Metadata\ApiResource;
-use ApiPlatform\Metadata\Get;
-use ApiPlatform\Metadata\GetCollection;
 use App\Repository\SargassumObservationRepository;
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Collection;
@@ -16,12 +13,6 @@ use Symfony\Component\Uid\Uuid;
 #[ORM\Entity(repositoryClass: SargassumObservationRepository::class)]
 #[ORM\Index(columns: ['detected_at'], name: 'idx_observation_detected_at')]
 #[ORM\Index(columns: ['source'], name: 'idx_observation_source')]
-#[ApiResource(
-    operations: [
-        new GetCollection(),
-        new Get(),
-    ]
-)]
 class SargassumObservation
 {
     #[ORM\Id]