UI: 容量按钮缩小、自定义默认空、保存验证、比例提示加"时，"

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

frontend/src/components/RecipeDetailOverlay.vue

@@ -165,7 +165,7 @@
             <select v-model.number="dilutionRatio" class="editor-select" style="width:60px">
               <option v-for="n in [3,4,5,6,7,8,9,10,12,15,20]" :key="n" :value="n">{{ n }}</option>
             </select>
-            <span class="ratio-hint">纯精油总数约为 {{ editorSuggestedEo }} 滴，现在为 {{ editorEoDrops }} 滴</span>
+            <span class="ratio-hint">时，纯精油总数约为 {{ editorSuggestedEo }} 滴，现在为 {{ editorEoDrops }} 滴</span>
           </div>
         </div>