feat: Go 重写后端，替换 Python FastAPI

用 Go (Gin + GORM + SQLite) 重写整个后端：
- 单二进制部署，不依赖 Python/pip/SDK
- net/http 原生客户端，无 Cloudflare TLS 指纹问题
- 多阶段 Dockerfile：Node 构建前端 + Go 构建后端 + Alpine 运行
- 内存占用从 ~95MB 降至 ~3MB
- 完整保留所有 API 路由、JWT 认证、API Key 权限、审计日志

handlers/logs.go

@@ -0,0 +1,95 @@
+package handlers
+
+import (
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/gin-gonic/gin"
+
+	"airwallex-admin/models"
+)
+
+func ListCardLogs(c *gin.Context) {
+	pageNum, _ := strconv.Atoi(c.DefaultQuery("page_num", "0"))
+	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))
+
+	query := models.DB.Model(&models.CardLog{})
+
+	if v := c.Query("card_id"); v != "" {
+		query = query.Where("card_id = ?", v)
+	}
+	if v := c.Query("action"); v != "" {
+		query = query.Where("action = ?", v)
+	}
+
+	var total int64
+	query.Count(&total)
+
+	var logs []models.CardLog
+	query.Order("created_at DESC").
+		Offset(pageNum * pageSize).
+		Limit(pageSize).
+		Find(&logs)
+
+	if logs == nil {
+		logs = []models.CardLog{}
+	}
+
+	hasMore := int64((pageNum+1)*pageSize) < total
+
+	c.JSON(http.StatusOK, gin.H{
+		"items":     logs,
+		"page_num":  pageNum,
+		"page_size": pageSize,
+		"total":     total,
+		"has_more":  hasMore,
+	})
+}
+
+func ListAuditLogs(c *gin.Context) {
+	pageNum, _ := strconv.Atoi(c.DefaultQuery("page_num", "0"))
+	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))
+
+	query := models.DB.Model(&models.AuditLog{})
+
+	if v := c.Query("action"); v != "" {
+		query = query.Where("action = ?", v)
+	}
+	if v := c.Query("resource_type"); v != "" {
+		query = query.Where("resource_type = ?", v)
+	}
+	if v := c.Query("from_date"); v != "" {
+		if t, err := time.Parse("2006-01-02", v); err == nil {
+			query = query.Where("created_at >= ?", t)
+		}
+	}
+	if v := c.Query("to_date"); v != "" {
+		if t, err := time.Parse("2006-01-02", v); err == nil {
+			query = query.Where("created_at < ?", t.Add(24*time.Hour))
+		}
+	}
+
+	var total int64
+	query.Count(&total)
+
+	var logs []models.AuditLog
+	query.Order("created_at DESC").
+		Offset(pageNum * pageSize).
+		Limit(pageSize).
+		Find(&logs)
+
+	if logs == nil {
+		logs = []models.AuditLog{}
+	}
+
+	hasMore := int64((pageNum+1)*pageSize) < total
+
+	c.JSON(http.StatusOK, gin.H{
+		"items":     logs,
+		"page_num":  pageNum,
+		"page_size": pageSize,
+		"total":     total,
+		"has_more":  hasMore,
+	})
+}