chore: durcit la configuration pour la production

- mobile: externalise l'URL d'API via EXPO_PUBLIC_API_URL (repli localhost en dev)
- backend: .env.example adapté au projet (PostgreSQL, JWT, FRONTEND_URL, Redis)
- frontend/mobile: ajoute .env.example (+ exception gitignore front)
- mobile: supprime les 4 `any` (helper getApiError, type Feed, glyphMap Ionicons)
- backend: normalise le style PSR-12 via Pint (13 fichiers)

Tests backend 15/15, mobile tsc 0, Pint pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/app/Http/Controllers/Admin/AdminEmotionController.php

@@ -12,7 +12,7 @@ class AdminEmotionController extends Controller
     public function index(): JsonResponse
     {
         $emotions = Emotion::niveau(1)
-            ->with(['enfants' => fn($q) => $q->orderBy('nom')])
+            ->with(['enfants' => fn ($q) => $q->orderBy('nom')])
             ->orderBy('nom')
             ->get();