feat: 用户徽章与等级体系，积分经济管理重构

- 新增徽章系统：badge 服务与 handler、管理端配置页、BadgeChip/LevelBadge 展示组件
- 新增等级模型：model/level 及前端 levels 元数据
- 管理端经济模块拆分为 points/badges/levels 独立页面，EconomySettings 迁入设置
- 积分、签到、评论等服务适配等级与徽章逻辑

backend/handler/badge.go

@@ -0,0 +1,151 @@
+package handler
+
+import (
+	"errors"
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+
+	"github.com/freefire/jiang13-bbs/middleware"
+	"github.com/freefire/jiang13-bbs/service"
+)
+
+type badgeRequest struct {
+	Name  string `json:"name"`
+	Icon  string `json:"icon"`
+	Color string `json:"color"`
+}
+
+type badgeGrantRequest struct {
+	UserID uint `json:"user_id" binding:"required"`
+}
+
+// badgeError 按业务错误映射响应
+func badgeError(c *gin.Context, err error) {
+	switch {
+	case errors.Is(err, service.ErrBadgeNotFound):
+		c.JSON(http.StatusNotFound, gin.H{"error": err.Error()})
+	case errors.Is(err, service.ErrBadgeNameExists):
+		c.JSON(http.StatusConflict, gin.H{"error": err.Error()})
+	case errors.Is(err, service.ErrBadgeInvalid):
+		c.JSON(http.StatusBadRequest, gin.H{"error": "徽章名称（1-16 字）或颜色无效"})
+	case errors.Is(err, service.ErrBadgeUserGone):
+		c.JSON(http.StatusNotFound, gin.H{"error": err.Error()})
+	default:
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "徽章操作失败"})
+	}
+}
+
+// AdminListBadges 全部徽章（含持有数）
+func (h *Handlers) AdminListBadges(c *gin.Context) {
+	badges, err := h.Badge.List()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取徽章列表失败"})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"badges": badges})
+}
+
+// AdminCreateBadge 新建徽章
+func (h *Handlers) AdminCreateBadge(c *gin.Context) {
+	var req badgeRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "请求参数无效"})
+		return
+	}
+	badge, err := h.Badge.Create(req.Name, req.Icon, req.Color)
+	if err != nil {
+		badgeError(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"badge": badge})
+}
+
+// AdminUpdateBadge 修改徽章
+func (h *Handlers) AdminUpdateBadge(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "请求参数无效"})
+		return
+	}
+	var req badgeRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "请求参数无效"})
+		return
+	}
+	badge, err := h.Badge.Update(uint(id), req.Name, req.Icon, req.Color)
+	if err != nil {
+		badgeError(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"badge": badge})
+}
+
+// AdminDeleteBadge 删除徽章（级联删除授予记录）
+func (h *Handlers) AdminDeleteBadge(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "请求参数无效"})
+		return
+	}
+	if err := h.Badge.Delete(uint(id)); err != nil {
+		badgeError(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true})
+}
+
+// AdminGrantBadge 授予徽章（幂等）
+func (h *Handlers) AdminGrantBadge(c *gin.Context) {
+	claims := middleware.CurrentUser(c)
+	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "请求参数无效"})
+		return
+	}
+	var req badgeGrantRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "请求参数无效"})
+		return
+	}
+	if err := h.Badge.Grant(uint(id), req.UserID, claims.ID); err != nil {
+		badgeError(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true})
+}
+
+// AdminRevokeBadge 撤销授予
+func (h *Handlers) AdminRevokeBadge(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "请求参数无效"})
+		return
+	}
+	userID, err := strconv.ParseUint(c.Param("userId"), 10, 64)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "请求参数无效"})
+		return
+	}
+	if err := h.Badge.Revoke(uint(id), uint(userID)); err != nil {
+		badgeError(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true})
+}
+
+// AdminBadgeHolders 某徽章全部持有者（后台授予面板用）
+func (h *Handlers) AdminBadgeHolders(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "请求参数无效"})
+		return
+	}
+	holders, err := h.Badge.Holders(uint(id))
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取持有者失败"})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"holders": holders})
+}