Fix compatibilité MySQL : NULLS LAST et order withCount/select

- DbCompat::nullsLast() : syntaxe portable pgsql/mysql pour ORDER BY NULLS LAST
- RechercheController, ExportController : remplace 'nom ASC NULLS LAST' (pgsql only)
- CarteController : select() avant withCount() pour ne pas effacer le COUNT subquery

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

app/Http/Controllers/CarteController.php

@@ -21,8 +21,8 @@ class CarteController extends Controller
             ->whereHas('sources.releves')
             ->with([
                 'sources' => function ($q) {
-                    $q->withCount('releves')
-                      ->select('id', 'nom', 'lieu_id', 'status', 'annee_debut', 'annee_fin')
+                    $q->select('id', 'nom', 'lieu_id', 'status', 'annee_debut', 'annee_fin')
+                      ->withCount('releves')
                       ->orderBy('nom');
                 },
             ])

app/Http/Controllers/ExportController.php

@@ -90,7 +90,7 @@ class ExportController extends Controller
             $query->whereRaw('date_evenement <= ?', [$request->integer('annee_fin') . '-12-31']);
         }
 
-        $releves = $query->orderByRaw('nom ASC NULLS LAST')->get();
+        $releves = $query->orderByRaw(DbCompat::nullsLast('nom'))->get();
 
         if ($releves->isEmpty()) {
             return back()->with('error', 'Aucun relevé à exporter.');

app/Http/Controllers/RechercheController.php

@@ -88,8 +88,8 @@ class RechercheController extends Controller
         // ── Tri + pagination ────────────────────────────────────────────────
         $total    = $query->count();
         $resultats = $query
-            ->orderByRaw('nom ASC NULLS LAST')
-            ->orderByRaw('date_evenement ASC NULLS LAST')
+            ->orderByRaw(DbCompat::nullsLast('nom'))
+            ->orderByRaw(DbCompat::nullsLast('date_evenement'))
             ->paginate(25)
             ->withQueryString();