feat: 数据概览简化 + 用户管理增加余额/提现列

- 数据概览：去掉代付统计独立卡片，总收入中以小标签显示代付金额
- 数据概览：移除余额统计区块（余额改在用户管理中展示）
- 数据概览：恢复转化率卡片（唯一付费用户/总用户）
- 用户管理：用户列表新增「余额/提现」列，显示钱包余额和已提现金额
- 后端：DBUsersList 增加 user_balances 查询，返回 walletBalance 字段
- 后端：User model 添加 WalletBalance 非数据库字段
- 包含之前的小程序埋点和管理后台点击统计面板

Made-with: Cursor

soul-api/internal/handler/admin_track.go

@@ -0,0 +1,93 @@
+package handler
+
+import (
+	"encoding/json"
+	"net/http"
+	"time"
+
+	"soul-api/internal/database"
+
+	"github.com/gin-gonic/gin"
+)
+
+// AdminTrackStats GET /api/admin/track/stats 管理端-按钮/标签点击统计（按模块+action聚合）
+// 查询参数：period=today|week|month|all（默认 today）
+func AdminTrackStats(c *gin.Context) {
+	period := c.DefaultQuery("period", "today")
+	db := database.DB()
+
+	now := time.Now()
+	var since time.Time
+	switch period {
+	case "today":
+		since = time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
+	case "week":
+		since = now.AddDate(0, 0, -7)
+	case "month":
+		since = now.AddDate(0, -1, 0)
+	default:
+		since = time.Time{}
+	}
+
+	type trackRow struct {
+		Action    string `gorm:"column:action"`
+		Target    string `gorm:"column:target"`
+		ExtraData []byte `gorm:"column:extra_data"`
+		Count     int64  `gorm:"column:count"`
+	}
+
+	query := db.Table("user_tracks").
+		Select("action, COALESCE(target, '') as target, extra_data, COUNT(*) as count").
+		Group("action, COALESCE(target, ''), extra_data").
+		Order("count DESC")
+
+	if !since.IsZero() {
+		query = query.Where("created_at >= ?", since)
+	}
+
+	var rows []trackRow
+	query.Find(&rows)
+
+	type statItem struct {
+		Action string `json:"action"`
+		Target string `json:"target"`
+		Module string `json:"module"`
+		Page   string `json:"page"`
+		Count  int64  `json:"count"`
+	}
+
+	byModule := make(map[string][]statItem)
+	total := int64(0)
+
+	for _, r := range rows {
+		module := "other"
+		page := ""
+		if len(r.ExtraData) > 0 {
+			var extra map[string]interface{}
+			if json.Unmarshal(r.ExtraData, &extra) == nil {
+				if m, ok := extra["module"].(string); ok && m != "" {
+					module = m
+				}
+				if p, ok := extra["page"].(string); ok && p != "" {
+					page = p
+				}
+			}
+		}
+		item := statItem{
+			Action: r.Action,
+			Target: r.Target,
+			Module: module,
+			Page:   page,
+			Count:  r.Count,
+		}
+		byModule[module] = append(byModule[module], item)
+		total += r.Count
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"success":  true,
+		"period":   period,
+		"total":    total,
+		"byModule": byModule,
+	})
+}