feat: 非精油产品(drop_count=1)显示"份"而非"滴"

oils store新增 unitLabel/unitLabelPlural，根据 dropCount 判断：
- 精油(dropCount>1): 滴/drop
- 护肤品等(dropCount=1): 份/portion
影响: 配方卡片、个人配方、库存匹配、去重提示

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

frontend/src/views/RecipeManager.vue

@@ -1019,8 +1019,8 @@ async function checkDupName(name, ings, target = 'diary') {
       return false
     }
 
-    const existIngs = dupIngs.map(i => `${i.oil}${i.drops}滴`).join('、')
-    const newIngs = myIngs.map(i => `${i.oil}${i.drops}滴`).join('、')
+    const existIngs = dupIngs.map(i => `${i.oil}${i.drops}${oils.unitLabel(i.oil)}`).join('、')
+    const newIngs = myIngs.map(i => `${i.oil}${i.drops}${oils.unitLabel(i.oil)}`).join('、')
     const ok = await showConfirm(
       `${where}中已有同名配方「${currentName}」，内容不同：\n\n已有：${existIngs}\n新的：${newIngs}\n\n请改名后保存`,
       { okText: '改名', cancelText: '取消' }