首页工作空间适配新结构并支持加载失败重试、切换独立删除接口

- 工作空间结果树适配 createDate→flows→items 两级结构（flows 下文件平铺，兼容旧平铺结构）
- 删除接口切换：工作空间树删除改走 session 域独立接口 resultDelete（deleteWorkspaceResult），不依赖内容创作域
- 会话记录/工作空间列表加载失败：区分失败态与空态，提供重试按钮；工作空间懒加载失败后切回 tab 自动重试

Co-Authored-By: Claude <noreply@anthropic.com>

src/views/home/components/Sidebar.vue

@@ -47,12 +47,20 @@
 				</div>
 
 			</div>
+			<div v-else-if="historyFailed" class="panel-error">
+				<span class="panel-error-text">加载失败</span>
+				<button class="panel-retry-btn" @click="emit('retry-history')">重试</button>
+			</div>
 			<div v-else class="panel-empty">暂无会话记录</div>
 		</div>
 
 		<!-- 工作空间面板 -->
 		<div v-show="activeTab === 'workspace'" class="panel" v-loading="treeLoading">
-			<el-empty v-if="!treeLoading && treeNodes.length === 0" :image-size="48" description="暂无内容" />
+			<div v-if="!treeLoading && treeNodes.length === 0 && workspaceFailed" class="panel-error">
+				<span class="panel-error-text">加载失败</span>
+				<button class="panel-retry-btn" @click="emit('retry-workspace')">重试</button>
+			</div>
+			<el-empty v-else-if="!treeLoading && treeNodes.length === 0" :image-size="48" description="暂无内容" />
 			<div v-else class="panel-list">
 				<div v-for="dateNode in treeNodes" :key="dateNode.id" class="tree-date-group">
 					<div class="tree-date-label">{{ dateNode.label }}</div>
@@ -98,6 +106,11 @@ interface Props {
 	activeMenu: string;
 	activeHistoryId: string | null;
 	historyList: HistoryItem[];
+	// 会话记录 / 工作空间加载失败标记：失败时显示「加载失败 + 重试」错误态
+	historyFailed?: boolean;
+	workspaceFailed?: boolean;
+	// 工作空间是否已成功加载：懒加载成功后才不再触发；失败保持 false → 切回 tab 自动重试
+	workspaceLoaded?: boolean;
 	treeNodes: TreeNode[];
 	treeLoading: boolean;
 }
@@ -111,18 +124,23 @@ interface Emits {
 	(e: 'download-node', data: TreeNode): void;
 	(e: 'delete-node', data: TreeNode): void;
 	(e: 'load-workspace'): void;
+	(e: 'retry-history'): void;
+	(e: 'retry-workspace'): void;
 }
 
-const props = defineProps<Props>();
+const props = withDefaults(defineProps<Props>(), {
+	historyFailed: false,
+	workspaceFailed: false,
+	workspaceLoaded: false,
+});
 const emit = defineEmits<Emits>();
 
 const activeTab = ref<'history' | 'workspace'>('history');
-// 工作空间懒加载标记：首次切换到「工作空间」tab 时才通知父组件加载结果树，避免进入页面即拉取
-const workspaceLoaded = ref(false);
 const handleTabChange = (tab: 'history' | 'workspace') => {
 	activeTab.value = tab;
-	if (tab === 'workspace' && !workspaceLoaded.value) {
-		workspaceLoaded.value = true;
+	// 懒加载：仅在「工作空间」tab 且尚未成功加载过时通知父组件拉取结果树，避免进入页面即请求；
+	// 失败时父组件不置 workspaceLoaded，切回 tab 自动重试
+	if (tab === 'workspace' && !props.workspaceLoaded) {
 		emit('load-workspace');
 	}
 };
@@ -282,6 +300,34 @@ const handleDeleteNode = (data: TreeNode) => emit('delete-node', data);
 	padding: 32px 0;
 }
 
+/* 加载失败错误态：可区分「失败」与「空数据」，并提供重试入口 */
+.panel-error {
+	padding: 32px 0;
+	text-align: center;
+}
+
+.panel-error-text {
+	font-size: 12px;
+	color: #94a3b8;
+	margin-right: 8px;
+}
+
+.panel-retry-btn {
+	border: 1px solid #dbeafe;
+	background: #eff6ff;
+	color: #2563eb;
+	font-size: 12px;
+	padding: 4px 14px;
+	border-radius: 8px;
+	cursor: pointer;
+	transition: background 0.15s;
+	outline: none;
+
+	&:hover {
+		background: #dbeafe;
+	}
+}
+
 /* 历史记录条目 */
 .history-item {
 	display: flex;