Remove volume selector from recipe card view

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/RecipeDetailOverlay.vue

@@ -36,17 +36,6 @@
           >English</button>
         </div>
 
-        <!-- Volume selector -->
-        <div class="volume-controls card-volume-controls">
-          <button
-            v-for="(drops, ml) in VOLUME_DROPS"
-            :key="ml"
-            class="volume-btn"
-            :class="{ active: selectedCardVolume === ml }"
-            @click="onCardVolumeChange(ml)"
-          >{{ ml === '单次' ? '单次' : ml + 'ml' }}</button>
-        </div>
-
         <!-- QR / brand upload hint -->
         <div v-if="showBrandHint" class="brand-upload-hint">
           <span class="hint-icon">✨</span>