feat(workflow): add workflow engine, /workflows panel, /ultracode skill

将 feat/sdk-backend 分支中 workflow 相关的 20 个 commit 压缩为单 commit：

- 工作流引擎核心：phase / agent / parallel / pipeline 编排原语（packages/workflow-engine/）
- /workflows 面板：三区焦点布局（顶部 run tabs + 左侧 phase 侧栏 + 右侧 agent 列表）
- /ultracode skill：多 agent workflow 编排入口
- 进度存储 / journal / notification 系统
- WorkflowService 生命周期管理 + SentryErrorBoundary
- 脚本沙箱：禁用 dynamic import()、JSON args 防御性归一化
- journal 与 named-workflow 路径统一在 projectRoot
- 错误处理：parallel/pipeline hooks 错误日志、failure routing、semaphore abort
- workflow 工具升级为 core 工具 + PascalCase 命名

Co-Authored-By: glm-5.1 <zai-org@claude-code-best.win>

packages/workflow-engine/src/index.ts

@@ -0,0 +1,24 @@
+// @claude-code-best/workflow-engine
+// 确定性 JS 脚本编排引擎。零核心层运行时依赖，通过端口适配与世界对话。
+
+export * from './types.js'
+export * from './constants.js'
+export * from './ports.js'
+export * from './agentAdapter.js'
+export * from './engine/concurrency.js'
+export * from './engine/script.js'
+export * from './engine/journal.js'
+export * from './engine/budget.js'
+export * from './engine/structuredOutput.js'
+export * from './engine/namedWorkflows.js'
+export * from './engine/errors.js'
+export * from './engine/context.js'
+export * from './engine/hooks.js'
+export * from './engine/runWorkflow.js'
+export * from './progress/events.js'
+export {
+  createWorkflowTool,
+  type WorkflowToolDescriptor,
+} from './tool/WorkflowTool.js'
+export { workflowInputSchema, type WorkflowInput } from './tool/schema.js'
+export { WORKFLOW_TOOL_NAME } from './tool/constants.js'