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/views/dataset/DatasetListView.vue

@@ -118,7 +118,7 @@ onMounted(loadData)
     <template #actions="{ row }">
       <div class="action-buttons">
         <el-button type="primary" link size="small" @click="handlePreview(row)">
-          <i class="fa fa-eye" style="margin-right: 4px" />预览
+          <i class="fa fa-eye" style="margin-right: 4px" />详情
         </el-button>
         <el-button type="success" link size="small" @click="handleDownload(row)">
           <i class="fa fa-download" style="margin-right: 4px" />下载

frontend/src/views/dataset/datasetRecords.ts

@@ -0,0 +1,121 @@
+export type DatasetRecordKind = 'object' | 'primitive' | 'invalid'
+
+export interface DatasetRecord {
+  sourceIndex: number
+  displayIndex: number
+  raw: string
+  kind: DatasetRecordKind
+  value: unknown
+  error?: string
+}
+
+export interface DatasetRecordResult {
+  supported: boolean
+  records: DatasetRecord[]
+  error?: string
+}
+
+function isObjectRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === 'object' && value !== null && !Array.isArray(value)
+}
+
+function parseValue(raw: string, sourceIndex: number, displayIndex: number): DatasetRecord {
+  try {
+    const value: unknown = JSON.parse(raw)
+    return {
+      sourceIndex,
+      displayIndex,
+      raw,
+      kind: isObjectRecord(value) ? 'object' : 'primitive',
+      value,
+    }
+  } catch (error) {
+    return {
+      sourceIndex,
+      displayIndex,
+      raw,
+      kind: 'invalid',
+      value: raw,
+      error: error instanceof Error ? error.message : 'JSON 格式不正确',
+    }
+  }
+}
+
+/** 将 JSONL 或 JSON 文件解析为可逐条编辑的样本，保留原始物理位置。 */
+export function parseDatasetRecords(content: string, fileName: string): DatasetRecordResult {
+  const normalizedName = fileName.toLowerCase()
+  if (normalizedName.endsWith('.jsonl')) {
+    const records: DatasetRecord[] = []
+    content.split('\n').forEach((line, sourceIndex) => {
+      if (!line.trim()) return
+      records.push(parseValue(line, sourceIndex, records.length + 1))
+    })
+    return { supported: true, records }
+  }
+
+  if (normalizedName.endsWith('.json')) {
+    try {
+      const root: unknown = JSON.parse(content)
+      const values = Array.isArray(root) ? root : [root]
+      return {
+        supported: true,
+        records: values.map((value, sourceIndex) => ({
+          sourceIndex,
+          displayIndex: sourceIndex + 1,
+          raw: JSON.stringify(value),
+          kind: isObjectRecord(value) ? 'object' : 'primitive',
+          value,
+        })),
+      }
+    } catch (error) {
+      return {
+        supported: true,
+        records: [{
+          sourceIndex: 0,
+          displayIndex: 1,
+          raw: content,
+          kind: 'invalid',
+          value: content,
+          error: error instanceof Error ? error.message : 'JSON 格式不正确',
+        }],
+      }
+    }
+  }
+
+  return { supported: false, records: [] }
+}
+
+/** 仅替换目标样本；JSONL 中其他行（包括空行和原格式）保持不变。 */
+export function updateDatasetRecord(
+  content: string,
+  fileName: string,
+  sourceIndex: number,
+  nextValue: unknown,
+) {
+  const normalizedName = fileName.toLowerCase()
+  if (normalizedName.endsWith('.jsonl')) {
+    const lines = content.split('\n')
+    if (sourceIndex < 0 || sourceIndex >= lines.length) throw new Error('目标样本不存在')
+    lines[sourceIndex] = JSON.stringify(nextValue)
+    return lines.join('\n')
+  }
+
+  if (normalizedName.endsWith('.json')) {
+    let root: unknown
+    try {
+      root = JSON.parse(content)
+    } catch {
+      if (sourceIndex !== 0) throw new Error('目标样本不存在')
+      return JSON.stringify(nextValue, null, 2)
+    }
+    if (Array.isArray(root)) {
+      if (sourceIndex < 0 || sourceIndex >= root.length) throw new Error('目标样本不存在')
+      root[sourceIndex] = nextValue
+      return JSON.stringify(root, null, 2)
+    }
+    if (sourceIndex !== 0) throw new Error('目标样本不存在')
+    return JSON.stringify(nextValue, null, 2)
+  }
+
+  throw new Error('当前文件不支持逐条编辑')
+}