feat(admin): 完善站点设置、内容回收站与后台菜单分组

新增站点设置与内容管理（含已删除恢复/清除），用户页改用独有运营指标，并按概览/内容/成员与经济/站点重组侧栏。

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/handler/moderation.go

@@ -87,16 +87,91 @@ func (h *Handlers) AdminRejectComment(c *gin.Context) {
 	h.execModeration(c, h.Moderation.RejectComment)
 }
 
-// writeModerationError 映射审核业务错误为 HTTP 响应
+// ===== 内容库（帖子/评论 + 已删除回收站） =====
+
+func (h *Handlers) AdminContentCounts(c *gin.Context) {
+	c.JSON(http.StatusOK, h.Moderation.AdminContentCounts(middleware.CurrentActor(c)))
+}
+
+func (h *Handlers) AdminListPosts(c *gin.Context) {
+	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
+	items, total, err := h.Moderation.ListAdminPosts(
+		middleware.CurrentActor(c), c.Query("status"), c.Query("q"), page,
+	)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取帖子列表失败"})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"posts": nonNilSlice(items), "total": total, "page": page})
+}
+
+func (h *Handlers) AdminListComments(c *gin.Context) {
+	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
+	items, total, err := h.Moderation.ListAdminComments(
+		middleware.CurrentActor(c), c.Query("status"), c.Query("q"), page,
+	)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取评论列表失败"})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"comments": nonNilSlice(items), "total": total, "page": page})
+}
+
+func (h *Handlers) AdminSoftDeletePost(c *gin.Context) {
+	h.execContentAction(c, h.Moderation.SoftDeletePost)
+}
+
+func (h *Handlers) AdminRestorePost(c *gin.Context) {
+	h.execContentAction(c, h.Moderation.RestorePost)
+}
+
+func (h *Handlers) AdminPurgePost(c *gin.Context) {
+	h.execContentAction(c, h.Moderation.PurgePost)
+}
+
+func (h *Handlers) AdminSoftDeleteComment(c *gin.Context) {
+	h.execContentAction(c, h.Moderation.SoftDeleteComment)
+}
+
+func (h *Handlers) AdminRestoreComment(c *gin.Context) {
+	h.execContentAction(c, h.Moderation.RestoreComment)
+}
+
+func (h *Handlers) AdminPurgeComment(c *gin.Context) {
+	h.execContentAction(c, h.Moderation.PurgeComment)
+}
+
+func (h *Handlers) execContentAction(c *gin.Context, fn func(*service.Actor, uint) error) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
+	if err != nil || id == 0 {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "无效的 ID"})
+		return
+	}
+	if err := fn(middleware.CurrentActor(c), uint(id)); err != nil {
+		h.writeModerationError(c, err)
+		return
+	}
+	h.broadcastModerationChanged()
+	c.JSON(http.StatusOK, gin.H{"message": "操作成功"})
+}
+
+// writeModerationError 映射审核/内容库业务错误为 HTTP 响应
 func (h *Handlers) writeModerationError(c *gin.Context, err error) {
 	switch {
-	case errors.Is(err, gorm.ErrRecordNotFound):
+	case errors.Is(err, gorm.ErrRecordNotFound), errors.Is(err, service.ErrContentNotFound):
 		c.JSON(http.StatusNotFound, gin.H{"error": "内容不存在"})
 	case errors.Is(err, service.ErrModerationForbidden):
 		c.JSON(http.StatusForbidden, gin.H{"error": err.Error()})
-	case errors.Is(err, service.ErrNotPending):
+	case errors.Is(err, service.ErrNotPending),
+		errors.Is(err, service.ErrContentNotDeleted):
 		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
 	default:
+		msg := err.Error()
+		if msg == "帖子已在回收站" || msg == "帖子未被删除" ||
+			msg == "评论已在回收站" || msg == "评论未被删除" {
+			c.JSON(http.StatusBadRequest, gin.H{"error": msg})
+			return
+		}
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "操作失败"})
 	}
 }