新增客户标签库：管理员维护、员工选择

租户级标签 CRUD 与颜色预设；客户打标仅能从库中选择，设置页提供管理入口，列表筛选随标签库动态生成。

server/cmd/seed/main.go

@@ -154,6 +154,16 @@ func seed() {
 	}
 	model.DB.Create(&entries)
 
+	// 客户标签库（管理员维护，坐席选择）
+	customerTags := []model.CustomerTag{
+		{TenantID: tid, Name: "VIP客户", Color: "amber", SortOrder: 0},
+		{TenantID: tid, Name: "新客户", Color: "green", SortOrder: 1},
+		{TenantID: tid, Name: "活跃", Color: "blue", SortOrder: 2},
+		{TenantID: tid, Name: "沉默", Color: "orange", SortOrder: 3},
+		{TenantID: tid, Name: "企业客户", Color: "cyan", SortOrder: 4},
+	}
+	model.DB.Create(&customerTags)
+
 	// 团队快捷回复（独立模块；知识库「快捷回复模板」分类可逐步弃用）
 	quickReplies := []model.QuickReply{
 		{TenantID: tid, Scope: "team", Title: "打招呼", Content: "您好！欢迎来到客服云，请问有什么可以帮您的？", Shortcut: "nh", GroupName: "通用", Status: "published", UsageCount: 120},