fix(dashboard): correct model override enable checkbox default state

src/gateway/ui/pages/dashboard.js

@@ -780,6 +780,7 @@ function updateAssistantHealth(configData) {
         ${taskRows.map((task) => {
     const background = backgroundModels?.[task.key] ?? {};
     const delegationTier = delegation?.[task.key] ?? 'fast';
+    const backgroundEnabled = Boolean(backgroundModels?.[task.key] && background?.enabled !== false);
     return `
             <div class="p-3 border border-zinc-800 rounded-md bg-zinc-950/60">
               <div class="text-sm text-zinc-50 mb-2">${escapeHtml(task.label)}</div>
@@ -791,7 +792,7 @@ function updateAssistantHealth(configData) {
                   </select>
                 </label>
                 <label class="flex items-center gap-2 mt-5 md:mt-0">
-                  <input id="assist-bg-${task.key}-enabled" type="checkbox" ${background?.enabled === false ? '' : 'checked'} />
+                  <input id="assist-bg-${task.key}-enabled" type="checkbox" ${backgroundEnabled ? 'checked' : ''} />
                   <span class="text-xs text-zinc-400">Enable provider/model override</span>
                 </label>
                 <label class="flex flex-col gap-1">