fix: 4 bugs post-review (JSON, rangMagie, GM guard, inline styles)

- Trailing comma dans fr.json qui cassait le parsing JSON (critique)
- RANG_MAGICIEN utilisait val.name au lieu de val.label
- Bouton tirage MJ accessible aux non-GM (ajout guard game.user.isGM)
- style='flex:1' et style='display:none' externalisés dans roll.less

templates/roll-dialog.hbs

@@ -64,7 +64,7 @@
     <fieldSet>
       <legend>{{localize "HAMALRON.Label.difficulty"}}</legend>
       <div class="difficulty-row">
-        <select name="difficulty" class="difficulty-select" style="flex:1">
+        <select name="difficulty" class="difficulty-select"   class="difficulty-select-input">
           {{selectOptions
             difficultyChoices
             selected="soustension_oppose"
@@ -75,7 +75,7 @@
           <i class="fas fa-cards"></i>
         </button>
       </div>
-      <div id="drawn-card-info" class="drawn-card-info" style="display:none">
+      <div id="drawn-card-info" class="drawn-card-info">
         <span id="drawn-card-name"></span>
       </div>
     </fieldSet>