feat: 套装成本扣除配件价值后再分摊

芳香调理-香薰机¥375，家庭医生-香薰机+木盒¥475，全精油-香薰机+竹木架¥575

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

frontend/src/composables/useKitCost.js

@@ -37,9 +37,9 @@ export function useKitCost() {
     }
     if (totalBottlePrice === 0) return {}
 
-    // Proportional allocation — kit accessories treated as freebies,
+    // Proportional allocation — subtract accessory value, then cap at bottle price sum
-    // so oil cost = min(kit price, sum of bottle prices)
+    const oilBudget = kit.price - (kit.accessoryValue || 0)
-    const effectivePrice = Math.min(kit.price, totalBottlePrice)
+    const effectivePrice = Math.min(oilBudget, totalBottlePrice)
     const perDrop = {}
     for (const name of resolved) {
       const meta = oils.oilsMeta[name]

frontend/src/config/kits.js

@@ -1,11 +1,13 @@
 // doTERRA 套装配置
 // 价格和内容更新频率低，手动维护即可
 // bottleCount: 某种油在套装中的瓶数（用于成本分摊和可做次数计算，默认1）
+// accessoryValue: 配件价值（香薰机、木盒等），从套装价中扣除后再分摊到精油
 export const KITS = [
   {
     id: 'aroma',
     name: '芳香调理套装',
     price: 2950,
+    accessoryValue: 375, // 香薰机
     oils: [
       '茶树', '野橘', '椒样薄荷', '薰衣草',
       '芳香调理', '安定情绪', '保卫', '舒缓',
@@ -16,6 +18,7 @@ export const KITS = [
     id: 'family',
     name: '家庭医生套装',
     price: 2250,
+    accessoryValue: 475, // 香薰机375 + 木盒100
     oils: [
       '乳香', '茶树', '薰衣草', '柠檬', '椒样薄荷', '西班牙牛至',
       '乐活', '舒缓', '保卫', '顺畅呼吸',
@@ -53,6 +56,7 @@ export const KITS = [
       '柑橘清新', '顺畅呼吸', '净化清新', '赋活呼吸', '天然防护',
       '椰子油',
     ],
+    accessoryValue: 575, // 香薰机375 + 竹木架200
     // 115mL×1 + 30mL×6 = 295mL, 标准瓶115mL, 约2.57瓶
     bottleCount: { '椰子油': 2.57 },
   },