add trend UX + PHPStan level 6 clean (0 errors)

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

backend/src/Controller/SpotScoreController.php

@@ -63,6 +63,8 @@ class SpotScoreController extends AbstractController
 
     /**
      * Score à un instant précis (sans cache).
+     *
+     * @return array{value: int, level: string, distance: float|null, density: float|null, trend: string|null, computedAt: string}|null
      */
     private function loadScoreAt(string $spotId, \DateTimeImmutable $at): ?array
     {
@@ -81,6 +83,8 @@ class SpotScoreController extends AbstractController
     /**
      * Scores estimés par horizon à partir des forecasts les plus récents.
      * Retourne null si aucun forecast disponible.
+     *
+     * @return array<string, array{score: int, level: string, distanceKm: float, confidence: float, validAt: string}>|null
      */
     private function loadHorizonScores(string $spotId): ?array
     {
@@ -125,6 +129,10 @@ class SpotScoreController extends AbstractController
         return $horizons;
     }
 
+    /**
+     * @param array<string, mixed> $row
+     * @return array{value: int, level: string, distance: float|null, density: float|null, trend: string|null, computedAt: string}
+     */
     private function formatScore(array $row): array
     {
         return [