feat: 支持应用内多 SSH 终端标签页

- 新增 terminalTabs store 管理标签页状态
- 新增 TerminalWorkspaceView 终端工作区视图
- 修改 ConnectionsView 终端按钮改用标签页模式
- 修改 TerminalView 作为兼容入口自动跳转到工作区
- 同一连接默认只保留一个标签页
- 切换标签时保持各自 SSH 会话不断开

frontend/src/router/index.ts

@@ -24,16 +24,21 @@ const routes: RouteRecordRaw[] = [
         name: 'Transfers',
         component: () => import('../views/TransfersView.vue'),
       },
-      {
-        path: 'connections',
-        name: 'Connections',
-        component: () => import('../views/ConnectionsView.vue'),
-      },
+      {
+        path: 'connections',
+        name: 'Connections',
+        component: () => import('../views/ConnectionsView.vue'),
+      },
+      {
+        path: 'terminal',
+        name: 'TerminalWorkspace',
+        component: () => import('../views/TerminalWorkspaceView.vue'),
+      },
       {
         path: 'terminal/:id',
         name: 'Terminal',
         component: () => import('../views/TerminalView.vue'),
-      },
+      },
       {
         path: 'sftp/:id',
         name: 'Sftp',