feat: 数据集版本管理支持删除历史版本

DatasetVersionList 新增 next_version_number，API 与 Mock 补充删除版本接口与并发控制，DatasetVersionBar 增加删除操作并对初始版本与最后版本禁用，DatasetPreviewView 接入删除流程，回归脚本与设计走查同步。

frontend/src/mock/adapter.ts

@@ -27,7 +27,10 @@ import {
   activateDatasetVersion,
   appendDatasetVersion,
   createInitialVersionState,
+  deleteDatasetVersion,
+  DatasetVersionMutationError,
   getActiveDatasetVersion,
+  normalizeDatasetVersionState,
 } from './datasetVersions'
 import type { StoredDatasetVersion, StoredDatasetVersionState } from './datasetVersions'
 
@@ -83,7 +86,13 @@ function getVersionState(fileId: string): StoredDatasetVersionState {
   if (persisted) {
     try {
       const state = JSON.parse(persisted) as StoredDatasetVersionState
-      if (state.versions?.length && state.active_version_id) return state
+      if (state.versions?.length && state.active_version_id) {
+        const normalizedState = normalizeDatasetVersionState(state)
+        if (state.next_version_number !== normalizedState.next_version_number) {
+          persistVersionState(fileId, normalizedState)
+        }
+        return normalizedState
+      }
     } catch {
       // 版本数据损坏时回退到初始版本
     }
@@ -100,6 +109,14 @@ function versionMetadata(version: StoredDatasetVersion) {
   return metadata
 }
 
+function versionListResponse(state: StoredDatasetVersionState) {
+  return {
+    versions: state.versions.map(versionMetadata).sort((a, b) => b.version - a.version),
+    active_version_id: state.active_version_id,
+    next_version_number: state.next_version_number,
+  }
+}
+
 /** 通过路径 + method 匹配 mock 响应 */
 async function handleMock(config: AxiosRequestConfig) {
   await delay(150) // 模拟网络延迟
@@ -185,10 +202,7 @@ async function handleMock(config: AxiosRequestConfig) {
   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,
-    })
+    return ok(versionListResponse(state))
   }
   if (m && method === 'post') {
     const fileId = decodeURIComponent(m[1])
@@ -249,6 +263,30 @@ async function handleMock(config: AxiosRequestConfig) {
       ? ok({ version: versionMetadata(version), content: version.content })
       : fail('数据集版本不存在', 404)
   }
+  if (m && method === 'delete') {
+    const fileId = decodeURIComponent(m[1])
+    const versionId = decodeURIComponent(m[2])
+    const currentState = getVersionState(fileId)
+    if (params.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 = deleteDatasetVersion(currentState, versionId)
+    } catch (error) {
+      if (error instanceof DatasetVersionMutationError) {
+        return fail(error.message, error.status)
+      }
+      return fail('删除版本失败', 500)
+    }
+    try {
+      persistVersionState(fileId, nextState)
+    } catch {
+      return fail('浏览器 Mock 存储空间不足', 413)
+    }
+    return ok(versionListResponse(nextState))
+  }
 
   // ==================== 训练任务 ====================
   if (url === '/fine-tune' && method === 'get') return ok(mockFineTuneList)