fix(test): add deterministic order values in SongPdfTest

Specify explicit order values for SongGroup factories to avoid unique
constraint violations on the composite (song_id, order) key when
faker generates duplicate random values.

tests/Feature/SongPdfTest.php

@@ -264,12 +264,14 @@
         'song_id' => $song->id,
         'name' => 'Strophe 1',
         'color' => '#3b82f6',
+        'order' => 1,
     ]);
 
     $chorus = SongGroup::factory()->create([
         'song_id' => $song->id,
         'name' => 'Refrain',
         'color' => '#ef4444',
+        'order' => 2,
     ]);
 
     SongSlide::factory()->create([
@@ -332,6 +334,7 @@
     $group = SongGroup::factory()->create([
         'song_id' => $song->id,
         'name' => 'Verse',
+        'order' => 1,
     ]);
 
     SongSlide::factory()->create([