feat: 支持 AI 设计项目多会话交互

需求：用户可在同一设计项目中新建和切换会话，任务列表保持项目级共享。

实现：
- 增加会话选择、新建入口及本地数据迁移
- Conversation 独立消息、Brief、Quote 与流式状态
- 保留项目任务并修复 Task revision 与 ABA 异步竞态
- 保持 Enter 发送、Shift+Enter 换行及 IME 保护

tests/unit/sidebar-opencode-projects.test.tsx

@@ -371,8 +371,16 @@ describe('Sidebar project initialization flow', () => {
     const summary = {
       workspaceId: 'cloud-project',
       title: '云端概念设计',
-      turnRevision: 0,
       viewRevision: 0,
+      conversationCount: 1,
+      phase: 'shaping',
+      updatedAt: '2026-07-31T10:00:00Z',
+    };
+    const conversation = {
+      conversationId: 'cloud-conversation',
+      workspaceId: 'cloud-project',
+      title: '主会话',
+      turnRevision: 0,
       phase: 'shaping',
       brief: {
         version: 0,
@@ -382,8 +390,11 @@ describe('Sidebar project initialization flow', () => {
         ready: false,
         missingDecision: '作品形式',
       },
+      createdAt: '2026-07-31T10:00:00Z',
       updatedAt: '2026-07-31T10:00:00Z',
+      messages: [],
     };
+    const { messages: _messages, ...conversationSummary } = conversation;
     const bootstrap = {
       capabilities: {
         conversation: true,
@@ -398,7 +409,20 @@ describe('Sidebar project initialization flow', () => {
         return { success: true, data: bootstrap };
       }
       if (path === '/api/works/image-workspace/workspaces/cloud-project' && !init?.method) {
-        return { success: true, data: { ...summary, messages: [] } };
+        return { success: true, data: { ...summary, conversations: [conversationSummary] } };
+      }
+      if (path === '/api/works/image-workspace/workspaces/cloud-project/conversations/cloud-conversation') {
+        return { success: true, data: conversation };
+      }
+      if (path === '/api/works/image-workspace/workspaces/cloud-project-two/conversations/cloud-conversation-two') {
+        return {
+          success: true,
+          data: {
+            ...conversation,
+            workspaceId: 'cloud-project-two',
+            conversationId: 'cloud-conversation-two',
+          },
+        };
       }
       if (path === '/api/works/image-workspace/workspaces/cloud-project/tasks') {
         return { success: true, data: [] };
@@ -406,7 +430,16 @@ describe('Sidebar project initialization flow', () => {
       if (path === '/api/works/image-workspace/workspaces' && init?.method === 'POST') {
         return {
           success: true,
-          data: { ...summary, workspaceId: 'cloud-project-two', title: '角色设定', messages: [] },
+          data: {
+            ...summary,
+            workspaceId: 'cloud-project-two',
+            title: '角色设定',
+            conversations: [{
+              ...conversationSummary,
+              workspaceId: 'cloud-project-two',
+              conversationId: 'cloud-conversation-two',
+            }],
+          },
         };
       }
       throw new Error(`Unexpected path ${path}`);
@@ -451,8 +484,16 @@ describe('Sidebar project initialization flow', () => {
     const summary = {
       workspaceId: 'local-project',
       title: '概念设计',
-      turnRevision: 0,
       viewRevision: 0,
+      conversationCount: 1,
+      phase: 'shaping',
+      updatedAt: '2026-07-31T10:00:00Z',
+    };
+    const conversation = {
+      conversationId: 'local-conversation',
+      workspaceId: 'local-project',
+      title: '主会话',
+      turnRevision: 0,
       phase: 'shaping',
       brief: {
         version: 0,
@@ -462,8 +503,11 @@ describe('Sidebar project initialization flow', () => {
         ready: false,
         missingDecision: '作品形式',
       },
+      createdAt: '2026-07-31T10:00:00Z',
       updatedAt: '2026-07-31T10:00:00Z',
+      messages: [],
     };
+    const { messages: _messages, ...conversationSummary } = conversation;
     let bootstrap = {
       capabilities: {
         conversation: true,
@@ -478,7 +522,10 @@ describe('Sidebar project initialization flow', () => {
         return { success: true, data: bootstrap };
       }
       if (path === '/api/works/image-workspace/workspaces/local-project' && !init?.method) {
-        return { success: true, data: { ...summary, messages: [] } };
+        return { success: true, data: { ...summary, conversations: [conversationSummary] } };
+      }
+      if (path === '/api/works/image-workspace/workspaces/local-project/conversations/local-conversation') {
+        return { success: true, data: conversation };
       }
       if (path === '/api/works/image-workspace/workspaces/local-project/tasks') {
         return { success: true, data: [] };
@@ -488,11 +535,25 @@ describe('Sidebar project initialization flow', () => {
           ...summary,
           workspaceId: 'local-project-two',
           title: '角色设计',
-          messages: [],
+          conversations: [{
+            ...conversationSummary,
+            workspaceId: 'local-project-two',
+            conversationId: 'local-conversation-two',
+          }],
         };
         bootstrap = { ...bootstrap, workspaces: [created, ...bootstrap.workspaces] };
         return { success: true, data: created };
       }
+      if (path === '/api/works/image-workspace/workspaces/local-project-two/conversations/local-conversation-two') {
+        return {
+          success: true,
+          data: {
+            ...conversation,
+            workspaceId: 'local-project-two',
+            conversationId: 'local-conversation-two',
+          },
+        };
+      }
       throw new Error(`Unexpected path ${path}`);
     });