fix: remove leftover document button in mobile sidebar footer

Co-authored-by: CodeFree <codefree@chinatelcom.cn>

app/components/agent/AgentSidebar.vue

@@ -122,10 +122,6 @@ const isAdmin = computed(() => props.user?.role === "admin");
 
           <div class="sidebar-footer">
             <div v-if="loggedIn" class="footer-links">
-              <button class="footer-link" @click="emit('showDocuments')">
-                <Icon name="lucide:file-text" />
-                <span>文档</span>
-              </button>
               <NuxtLink to="/settings" class="footer-link">
                 <Icon name="lucide:settings" />
                 <span>设置</span>