feat(core): build_event_payload 统一信封 — 28 处事件发布全部迁移

- erp-core 添加 build_event_payload()，自动注入 schema_version + occurred_at
- erp-health 12 个 service（25 处）、erp-auth（1 处）、erp-workflow（2 处）
  全部迁移到统一信封格式

crates/erp-workflow/src/module.rs

@@ -115,11 +115,11 @@ impl WorkflowModule {
                                 let event = erp_core::events::DomainEvent::new(
                                     "task.timeout",
                                     *tenant_id,
-                                    serde_json::json!({
+                                    erp_core::events::build_event_payload(serde_json::json!({
                                         "task_id": task_id,
                                         "instance_id": instance_id,
                                         "assignee_id": assignee_id,
-                                    }),
+                                    })),
                                 );
                                 event_bus.publish(event, &db).await;
                             }

crates/erp-workflow/src/service/instance_service.rs

@@ -126,7 +126,7 @@ impl InstanceService {
         event_bus.publish(erp_core::events::DomainEvent::new(
             "process_instance.started",
             tenant_id,
-            serde_json::json!({ "instance_id": instance_id, "definition_id": definition.id, "started_by": operator_id }),
+            erp_core::events::build_event_payload(serde_json::json!({ "instance_id": instance_id, "definition_id": definition.id, "started_by": operator_id })),
         ), db).await;
 
         audit_service::record(
@@ -323,7 +323,7 @@ impl InstanceService {
             tenant_id: Set(tenant_id),
             event_type: Set(event_type),
             payload: Set(Some(
-                serde_json::json!({ "instance_id": id, "changed_by": operator_id }),
+                erp_core::events::build_event_payload(serde_json::json!({ "instance_id": id, "changed_by": operator_id })),
             )),
             correlation_id: Set(Some(Uuid::now_v7())),
             status: Set("pending".to_string()),