删除会话管理功能，修复会话id为空问题

charging_web_app/src/app/(authenticated)/admin/dashboard/page.tsx

@@ -188,12 +188,6 @@ const AdminDashboardPage = () => {
                             href="/admin/robots"
                             icon={<FiTerminal size={28}/>}
                         />
-                        <NavCard 
-                            title="会话管理"
-                            description="查看所有充电会话记录、详情"
-                            href="/admin/sessions"
-                            icon={<FiList size={28}/>}
-                        />
                         <NavCard 
                             title="用户管理"
                             description="查看和管理平台用户列表"

charging_web_app/src/app/(authenticated)/request-charging/page.tsx

@@ -68,10 +68,10 @@ export default function RequestChargingPage() {
             // Corrected path
             const response = await api.post('/session/request', { spotId: selectedSpotId });
             if (response.data && response.data.code === 0) {
-                const newSession = response.data.data;
+                const sessionId = response.data.data;
                 // TODO: Navigate to a session status page or show success message
                 // For now, navigate to dashboard and show an alert
-                alert(`充电请求成功！会话ID: ${newSession.id}. 机器人正在前往...`);
+                alert(`充电请求成功！会话ID: ${sessionId}. 机器人正在前往...`);
                 router.push('/dashboard'); 
             } else {
                 setError(response.data.message || '发起充电请求失败');