UI: 商业核算排版优化

- 消耗分析：同时用完不显示"最先消耗完"，去掉"最多"
- 项目卡片：鼠标悬停显示删除按钮
- 表头：精油/用量/每滴/小计，避免手机换行
- 删除按钮缩小
- 价格计算：标签和值间距缩短
- 构建时间改为英国时区

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

frontend/vite.config.js

@@ -1,7 +1,7 @@
 import { defineConfig } from 'vite'
 import vue from '@vitejs/plugin-vue'
 
-const buildTime = new Date().toLocaleString('zh-CN', { timeZone: 'Asia/Shanghai', month: '2-digit', day: '2-digit', hour: '2-digit', minute: '2-digit' })
+const buildTime = new Date().toLocaleString('en-GB', { timeZone: 'Europe/London', month: '2-digit', day: '2-digit', hour: '2-digit', minute: '2-digit' })
 
 export default defineConfig({
   define: {