feat: 数据集版本管理

新增数据集版本创建、切换、激活与历史追溯能力，Mock 通过 localStorage 持久化版本状态并接入版本接口路由，预览页支持版本对比与内容回滚，列表补充版本入口，回归脚本扩充断言。

frontend/src/mock/adapter.ts

@@ -22,6 +22,13 @@ import {
   mockTrainingLogFiles,
   mockLogContent,
 } from './data'
+import {
+  activateDatasetVersion,
+  appendDatasetVersion,
+  createInitialVersionState,
+  getActiveDatasetVersion,
+} from './datasetVersions'
+import type { StoredDatasetVersion, StoredDatasetVersionState } from './datasetVersions'
 
 /** 模拟网络延迟 */
 function delay(ms = 200): Promise<void> {
@@ -57,6 +64,41 @@ function stripBaseURL(url: string): string {
   return path
 }
 
+function datasetFallbackContent(fileId: string) {
+  const fallbackKey = fileId.endsWith('-readme') ? 'mock-readme' : 'mock-jsonl'
+  return mockDatasetPreviews[fileId] ?? mockDatasetPreviews[fallbackKey] ?? ''
+}
+
+function versionStorageKey(fileId: string) {
+  return `mock:dataset-versions:${fileId}`
+}
+
+function persistVersionState(fileId: string, state: StoredDatasetVersionState) {
+  localStorage.setItem(versionStorageKey(fileId), JSON.stringify(state))
+}
+
+function getVersionState(fileId: string): StoredDatasetVersionState {
+  const persisted = localStorage.getItem(versionStorageKey(fileId))
+  if (persisted) {
+    try {
+      const state = JSON.parse(persisted) as StoredDatasetVersionState
+      if (state.versions?.length && state.active_version_id) return state
+    } catch {
+      // 版本数据损坏时回退到初始版本
+    }
+  }
+
+  const legacyContent = localStorage.getItem(`mock:dataset-file:${fileId}`)
+  const state = createInitialVersionState(legacyContent ?? datasetFallbackContent(fileId))
+  persistVersionState(fileId, state)
+  return state
+}
+
+function versionMetadata(version: StoredDatasetVersion) {
+  const { content: _content, ...metadata } = version
+  return metadata
+}
+
 /** 通过路径 + method 匹配 mock 响应 */
 async function handleMock(config: AxiosRequestConfig) {
   await delay(150) // 模拟网络延迟
@@ -133,9 +175,77 @@ async function handleMock(config: AxiosRequestConfig) {
   m = url.match(/^\/dataset-manage\/preview\/([^/]+)$/)
   if (m && method === 'get') {
     const fileId = decodeURIComponent(m[1])
-    const fallbackKey = fileId.endsWith('-readme') ? 'mock-readme' : 'mock-jsonl'
-    const content = mockDatasetPreviews[fileId] ?? mockDatasetPreviews[fallbackKey]
-    return ok({ content })
+    return ok({ content: getActiveDatasetVersion(getVersionState(fileId)).content })
+  }
+  if (m && method === 'put') return fail('历史版本不可覆盖，请创建新版本', 405)
+
+  m = url.match(/^\/dataset-manage\/versions\/([^/]+)$/)
+  if (m && method === 'get') {
+    const fileId = decodeURIComponent(m[1])
+    const state = getVersionState(fileId)
+    return ok({
+      versions: state.versions.map(versionMetadata).sort((a, b) => b.version - a.version),
+      active_version_id: state.active_version_id,
+    })
+  }
+  if (m && method === 'post') {
+    const fileId = decodeURIComponent(m[1])
+    if (typeof body.content !== 'string') return fail('文件内容格式不正确', 400)
+    const currentState = getVersionState(fileId)
+    if (body.expected_current_version_id !== currentState.active_version_id) {
+      return fail('当前版本已被其他用户更新，请刷新后重试', 409)
+    }
+    if (body.base_version_id !== currentState.active_version_id) {
+      return fail('只能基于当前版本创建新版本', 409)
+    }
+    if (body.content === getActiveDatasetVersion(currentState).content) {
+      return fail('数据内容没有变化，无需创建新版本', 400)
+    }
+    const nextState = appendDatasetVersion(
+      currentState,
+      body.content,
+      new Date().toISOString(),
+      typeof body.description === 'string' ? body.description : '在线编辑',
+    )
+    try {
+      persistVersionState(fileId, nextState)
+    } catch {
+      return fail('文件内容过大，浏览器 Mock 存储空间不足', 413)
+    }
+    const version = getActiveDatasetVersion(nextState)
+    return ok({ version: versionMetadata(version), content: version.content })
+  }
+
+  m = url.match(/^\/dataset-manage\/versions\/([^/]+)\/active$/)
+  if (m && method === 'put') {
+    const fileId = decodeURIComponent(m[1])
+    const currentState = getVersionState(fileId)
+    if (body.expected_current_version_id !== currentState.active_version_id) {
+      return fail('当前版本已被其他用户更新，请刷新后重试', 409)
+    }
+    let nextState: StoredDatasetVersionState
+    try {
+      nextState = activateDatasetVersion(currentState, String(body.version_id || ''))
+    } catch (error) {
+      return fail(error instanceof Error ? error.message : '版本不存在', 404)
+    }
+    try {
+      persistVersionState(fileId, nextState)
+    } catch {
+      return fail('浏览器 Mock 存储空间不足', 413)
+    }
+    const version = getActiveDatasetVersion(nextState)
+    return ok({ version: versionMetadata(version), content: version.content })
+  }
+
+  m = url.match(/^\/dataset-manage\/versions\/([^/]+)\/([^/]+)$/)
+  if (m && method === 'get') {
+    const fileId = decodeURIComponent(m[1])
+    const versionId = decodeURIComponent(m[2])
+    const version = getVersionState(fileId).versions.find((item) => item.id === versionId)
+    return version
+      ? ok({ version: versionMetadata(version), content: version.content })
+      : fail('数据集版本不存在', 404)
   }
 
   // ==================== 训练任务 ====================