refactor(ui): standardize button types and migrate file operations to V3 Action API

src/routes/events/[event_id]/(badges)/badges/+page.svelte

@@ -309,10 +309,10 @@
 
 {#if $ae_loc.trusted_access}
     <div class="mt-4 text-center">
-        <button class="btn btn-primary" onclick={() => (show_create_badge_modal = true)}>
+        <button type="button" class="btn btn-primary" onclick={() => (show_create_badge_modal = true)}>
             <span class="fas fa-plus mr-2"></span> Add New Badge
         </button>
-        <button class="btn btn-primary ml-2" onclick={() => (show_upload_badge_modal = true)}>
+        <button type="button" class="btn btn-primary ml-2" onclick={() => (show_upload_badge_modal = true)}>
             <span class="fas fa-upload mr-2"></span> Upload Badge List
         </button>
     </div>