feat(ai): 业务上下文感知与 A2UI 链路统一

- 新增代码内业务上下文元数据层（实体字典 + 三大闭环工作流）
- 新增 get_business_context / get_entity_schema / get_pending_tasks 运行时工具
- SYSTEM_PROMPT 与技能目录改为先查业务流程/待办再执行
- A2UI 增加 ai_a2ui_submissions 幂等表、表单过期、ui.artifact 事件
- 提交回灌携带 submissionId / fieldErrors / 下一步建议
- 前端 uiArtifacts 归一化与过期表单禁用

apps/server/src/app.module.ts

@@ -19,6 +19,7 @@ import { AddA2UiReviews1784880000000 } from './migrations/1784880000000-AddA2UiR
 import { AddImportRuns1784910000000 } from './migrations/1784910000000-AddImportRuns';
 import { DropAiMessageFeedback1784920000000 } from './migrations/1784920000000-DropAiMessageFeedback';
 import { AddImportRunSettings1784930000000 } from './migrations/1784930000000-AddImportRunSettings';
+import { AddA2UiSubmissions1786001000000 } from './migrations/1786001000000-AddA2UiSubmissions';
 const allMigrations = [
   InitialSchema1784520727860,
   AddExamManagement1784600000000,
@@ -31,6 +32,7 @@ const allMigrations = [
   AddImportRuns1784910000000,
   DropAiMessageFeedback1784920000000,
   AddImportRunSettings1784930000000,
+  AddA2UiSubmissions1786001000000,
 ];
 import { AuthorizationModule } from './authorization';
 import { RbacModule } from './rbac/rbac.module';
@@ -149,6 +151,7 @@ import { IntegrationConfigModule } from './integration/config/config.module';
           Entities.AiAttachment,
           Entities.AiForm,
           Entities.AiReview,
+          Entities.AiA2uiSubmission,
           Entities.ImportRun,
           Entities.ImportStep,
           Entities.ImportRow,