feat(agent): 사이드바에 ‘에이전트 관리’ 메뉴 및 라우트/기본 뷰 추가

- router: /agent/list, /agent/settlement-ratio 라우트 등록
- SideMenu: ‘크리에이터 관리’ 바로 아래 ‘에이전트 관리’ 섹션 동적 삽입
- views: AgentList.vue, AgentSettlementRatio.vue 스텁 추가

src/router/index.js

@@ -50,6 +50,17 @@ const routes = [
                 name: 'CreatorReview',
                 component: () => import(/* webpackChunkName: "counselor" */ '../views/Creator/CreatorSettlementRatio.vue')
             },
+            // Agent Management
+            {
+                path: '/agent/list',
+                name: 'AgentList',
+                component: () => import(/* webpackChunkName: "agent" */ '../views/Agent/AgentList.vue')
+            },
+            {
+                path: '/agent/settlement-ratio',
+                name: 'AgentSettlementRatio',
+                component: () => import(/* webpackChunkName: "agent" */ '../views/Agent/AgentSettlementRatio.vue')
+            },
             {
                 path: '/live/tags',
                 name: 'LiveTags',