fix: 管理配方容量显示支持产品，混合g/ml统一显示ml

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

frontend/src/components/RecipeCard.vue

@@ -56,15 +56,15 @@ const volumeLabel = computed(() => {
     if (ml <= 2) return '单次'
     return `${Math.round(ml)}ml`
   }
-  // Non-coconut: sum portion products by unit
-  const unitSums = {}
+  // Non-coconut: sum all portion products as ml
+  let totalMl = 0
+  let hasProduct = false
   for (const ing of ings) {
     if (!oilsStore.isPortionUnit(ing.oil)) continue
-    const u = oilsStore.unitLabel(ing.oil)
-    unitSums[u] = (unitSums[u] || 0) + (ing.drops || 0)
+    hasProduct = true
+    totalMl += ing.drops || 0
   }
-  const parts = Object.entries(unitSums).map(([u, v]) => `${Math.round(v)}${u}`)
-  if (parts.length) return parts.join('+')
+  if (hasProduct && totalMl > 0) return `${Math.round(totalMl)}ml`
   return ''
 })
 </script>