feat: add FlightImage model and update Flight image relation

app/Models/Flight.php

@@ -156,5 +156,16 @@ class Flight extends Model
     {
         return $this->hasMany(Favorite::class);
     }
+    public function images()
+    {
+        return $this->hasMany(FlightImage::class)
+            ->orderBy('sort_order');
+    }
+
+    public function coverImage()
+    {
+        return $this->hasOne(FlightImage::class)
+            ->where('is_default', true);
+    }
 
 }