fix: eoDrops变量提到volume分支外，修复编辑配方报错

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

frontend/src/views/RecipeManager.vue

@@ -777,15 +777,15 @@ function editRecipe(recipe) {
   const coco = ings.find(i => i.oil === '椰子油')
   if (coco) {
     formCocoRow.value = { ...coco, _search: '椰子油', _open: false }
+    const eoDrops = ings.filter(i => i.oil && i.oil !== '椰子油').reduce((s, i) => s + (i.drops || 0), 0)
     // Use stored volume if available, otherwise guess from drops
     if (recipe.volume) {
       formVolume.value = recipe.volume
       if (recipe.volume === 'custom') {
-        const totalDrops = ings.reduce((s, i) => s + (i.drops || 0), 0)
+        const totalDrops = eoDrops + coco.drops
         formCustomVolume.value = Math.round(totalDrops / DROPS_PER_ML)
       }
     } else {
-      const eoDrops = ings.filter(i => i.oil && i.oil !== '椰子油').reduce((s, i) => s + (i.drops || 0), 0)
       const totalDrops = eoDrops + coco.drops
       const ml = totalDrops / DROPS_PER_ML
       if (ml <= 2) formVolume.value = 'single'