Wire Qwen Enhance prompt toggle through Studio 2 and the runner.

Queue PE first when enabled, fail closed on parse_ok, free VRAM, then run the existing T2I or Edit graph with the rewrite.

Co-authored-by: Cursor <cursoragent@cursor.com>

components/studio2/Mobile.vue

@@ -158,6 +158,7 @@
     </template>
     <template v-else>
      <label class="m-label">Prompt<textarea v-model="ctx.form.promptSections.action" rows="5" class="m-area" placeholder="Describe the image or the shot." /></label>
+     <label v-if="ctx.form.engine==='qwen21' && (ctx.form.mode==='generate' || ctx.form.mode==='edit')" class="m-check"><input v-model="ctx.form.enhancePrompt" type="checkbox"> Enhance prompt</label>
      <div>
       <span class="m-label">Negative prompt</span>
       <div class="m-neg">