合并 AI 设计多会话客户端

整合 Enter 发送与多会话交互，保留服务端持久 Conversation Session，并补齐迁移、回归、Electron E2E 与 canonical 文档。

tests/unit/local-image-workspace.test.ts

@@ -1,4 +1,11 @@
-import { existsSync, mkdtempSync, readFileSync, rmSync } from 'node:fs';
+import {
+  existsSync,
+  mkdirSync,
+  mkdtempSync,
+  readFileSync,
+  rmSync,
+  writeFileSync,
+} from 'node:fs';
 import { tmpdir } from 'node:os';
 import { join } from 'node:path';
 import { afterEach, describe, expect, it } from 'vitest';
@@ -87,18 +94,96 @@ describe('local AI design workspace', () => {
 
     const reloaded = new LocalImageWorkspace({ userDataDir });
     await expect(reloaded.bootstrap()).resolves.toMatchObject({
-      workspaces: [{ title: '角色设计第二版', turnRevision: 0, viewRevision: 1 }],
+      workspaces: [{ title: '角色设计第二版', conversationCount: 1, viewRevision: 1 }],
     });
   });
 
+  it('migrates a legacy single conversation into schema v3 without losing project tasks', async () => {
+    const userDataDir = createTemporaryDirectory();
+    const rootDirectory = getLocalImageWorkspaceDirectory(userDataDir);
+    const timestamp = '2026-07-31T10:00:00.000Z';
+    mkdirSync(rootDirectory, { recursive: true });
+    writeFileSync(join(rootDirectory, 'design-workspace-v2.json'), JSON.stringify({
+      schemaVersion: 2,
+      workspaces: [{
+        workspaceId: 'workspace-legacy',
+        clientWorkspaceId: 'client-legacy',
+        title: '历史设计项目',
+        turnRevision: 2,
+        viewRevision: 4,
+        phase: 'awaiting_confirmation',
+        brief: {
+          version: 2,
+          status: 'ready',
+          medium: 'image',
+          summary: '历史海报',
+          ready: true,
+          missingDecision: null,
+        },
+        messages: [{
+          id: 'message-legacy',
+          role: 'user',
+          kind: 'user',
+          text: '保留这条历史消息',
+          quickReplies: [],
+          generationQuote: null,
+          turnRevision: 1,
+          createdAt: timestamp,
+        }],
+        requestHashes: { 'turn-legacy': 'hash-legacy' },
+        updatedAt: timestamp,
+      }],
+      tasksByWorkspaceId: {
+        'workspace-legacy': [{
+          taskId: 'task-legacy',
+          workspaceId: 'workspace-legacy',
+          medium: 'image',
+          status: 'succeeded',
+          briefVersion: 2,
+          briefSummary: '历史海报',
+          quoteId: null,
+          quotedDesignPoints: null,
+          failureCode: null,
+          resultAssets: [],
+          createdAt: timestamp,
+          updatedAt: timestamp,
+        }],
+      },
+      assetsById: {},
+    }), 'utf8');
+    const service = createService(userDataDir);
+
+    const workspace = await service.getWorkspace('workspace-legacy');
+    const migratedConversation = workspace.conversations[0];
+
+    expect(workspace).toMatchObject({
+      workspaceId: 'workspace-legacy',
+      conversationCount: 1,
+      conversations: [{ title: '历史会话', turnRevision: 2 }],
+    });
+    await expect(service.getConversation(
+      'workspace-legacy',
+      migratedConversation.conversationId,
+    )).resolves.toMatchObject({
+      messages: [{ text: '保留这条历史消息' }],
+    });
+    await expect(service.listTasks('workspace-legacy')).resolves.toMatchObject([{
+      taskId: 'task-legacy',
+      conversationId: migratedConversation.conversationId,
+    }]);
+    expect(existsSync(join(rootDirectory, 'design-workspace-v3.json'))).toBe(true);
+  });
+
   it('creates a Quote first and a visible generation task only after confirmation', async () => {
     const service = createService(createTemporaryDirectory());
     const created = await service.createWorkspace({
       clientWorkspaceId: 'client-flow',
       title: '海洋公益海报',
     });
+    const conversationId = created.conversations[0].conversationId;
     const discussed = await service.submitMessage({
       workspaceId: created.workspaceId,
+      conversationId,
       clientTurnId: 'turn-one',
       expectedTurnRevision: 0,
       message: '做一张保护海洋的竖版公益海报',
@@ -111,6 +196,7 @@ describe('local AI design workspace', () => {
 
     const confirmed = await service.confirmGeneration({
       workspaceId: created.workspaceId,
+      conversationId,
       clientTurnId: 'turn-two',
       expectedTurnRevision: 1,
       quoteId: quote!.quoteId,
@@ -141,15 +227,17 @@ describe('local AI design workspace', () => {
       clientWorkspaceId: 'client-reset',
       title: '可重置项目',
     });
+    const conversationId = created.conversations[0].conversationId;
 
     await expect(service.submitMessage({
       workspaceId: created.workspaceId,
+      conversationId,
       clientTurnId: 'stale-turn',
       expectedTurnRevision: 3,
       message: '测试',
     })).rejects.toMatchObject<LocalImageWorkspaceError>({
       status: 409,
-      code: 'workspace_revision_conflict',
+      code: 'conversation_revision_conflict',
     });
 
     expect(existsSync(getLocalImageWorkspaceDirectory(userDataDir))).toBe(true);