优化钱包界面：改名积分明细，添加筛选功能，优化表格列宽

- 侧边栏和页面标题改为'积分明细'
- 新增关联单号、收支类型筛选功能
- 后端 ledger API 支持 reference_no 和 type 筛选参数
- 表格列宽优化，流水号完整展示，备注列限制宽度
- 隐藏固定 tab 模式下的商户介绍文字

frontend/src/layouts/MainLayout.tsx

@@ -78,7 +78,7 @@ const adminSections: SidebarSection[] = [
     key: 'funds',
     label: '资金',
     icon: <WalletOutlined />,
-    children: [{ key: 'merchant-wallet', label: '钱包', path: '/merchant-wallet' }],
+    children: [{ key: 'merchant-wallet', label: '积分明细', path: '/merchant-wallet' }],
   },
   {
     key: 'open-api',
@@ -116,7 +116,7 @@ const merchantSections: SidebarSection[] = [
     key: 'funds',
     label: '资金',
     icon: <WalletOutlined />,
-    children: [{ key: 'merchant-wallet', label: '钱包', path: '/merchant-wallet' }],
+    children: [{ key: 'merchant-wallet', label: '积分明细', path: '/merchant-wallet' }],
   },
   {
     key: 'staff',