fix: 设计原则审查修复 — DIP/ISP, LoD, DRY, OCP, URL, 301缓存

- P0 DIP+ISP: 全链路注入接口，消除零接口紧耦合
- P0 URL: auth 301→302，修复登出后浏览器缓存陷阱
- P1 DRY: JWT 认证逻辑收敛至 TokenService+中间件
- P2 DRY: 前后端角色/状态映射统一为 model 常量
- P2 LoD: 新增 SettingsController，router 不再跨层调 repo
- P2 URL: settings ?tab= → /settings/:tab 伪静态
- P3 OCP: 角色权限 map 化，告别硬编码 switch

internal/controller/admin/admin_controller.go

@@ -11,13 +11,15 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
+// Note: service import kept for ListUsersParams / ListUsersResult DTOs
+
 // AdminController 管理后台控制器
 type AdminController struct {
-	adminService *service.AdminService
+	adminService adminUseCase
 }
 
 // NewAdminController 构造函数
-func NewAdminController(adminService *service.AdminService) *AdminController {
+func NewAdminController(adminService adminUseCase) *AdminController {
 	return &AdminController{adminService: adminService}
 }
 
@@ -31,9 +33,11 @@ func (ac *AdminController) Dashboard(c *gin.Context) {
 // UsersPage 用户管理页面
 func (ac *AdminController) UsersPage(c *gin.Context) {
 	c.HTML(http.StatusOK, "admin/users/index.html", common.BuildAdminPageData(c, gin.H{
-		"Title":    "用户管理",
-		"ExtraCSS": "/admin/static/css/users.css",
-		"ExtraJS":  "/admin/static/js/users.js",
+		"Title":       "用户管理",
+		"ExtraCSS":    "/admin/static/css/users.css",
+		"ExtraJS":     "/admin/static/js/users.js",
+		"RoleNames":   model.RoleDisplayNames,
+		"StatusNames": model.StatusDisplayNames,
 	}))
 }