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>

src/constants/tools.ts

@@ -32,7 +32,7 @@ import { TEAM_DELETE_TOOL_NAME } from '@claude-code-best/builtin-tools/tools/Tea
 import { EXECUTE_TOOL_NAME } from '@claude-code-best/builtin-tools/tools/ExecuteTool/constants.js'
 import { ENTER_WORKTREE_TOOL_NAME } from '@claude-code-best/builtin-tools/tools/EnterWorktreeTool/constants.js'
 import { EXIT_WORKTREE_TOOL_NAME } from '@claude-code-best/builtin-tools/tools/ExitWorktreeTool/constants.js'
-import { WORKFLOW_TOOL_NAME } from '@claude-code-best/builtin-tools/tools/WorkflowTool/constants.js'
+import { WORKFLOW_TOOL_NAME } from '@claude-code-best/workflow-engine'
 import {
   CRON_CREATE_TOOL_NAME,
   CRON_DELETE_TOOL_NAME,
@@ -165,6 +165,11 @@ export const CORE_TOOLS = new Set([
   LSP_TOOL_NAME, // 'LSP'
   // Skills
   SKILL_TOOL_NAME, // 'Skill'
+  // Workflow orchestration — first-class primitive /ultracode directs the
+  // model to call directly. Kept core (not deferred) so it's always visible
+  // and callable without a SearchExtraTools round-trip. Registration itself
+  // is still feature-gated (feature('WORKFLOW_SCRIPTS')) in tools.ts.
+  WORKFLOW_TOOL_NAME, // 'Workflow'
   // Scheduling & monitoring
   SLEEP_TOOL_NAME, // 'Sleep'
   // Tool discovery (always loaded)