feat(core): implement optimistic locking across all entities

Add VersionMismatch error variant and check_version() helper to erp-core.
All 13 mutable entities now enforce version checking on update/delete:
- erp-auth: user, role, organization, department, position
- erp-config: dictionary, dictionary_item, menu, setting, numbering_rule
- erp-workflow: process_definition, process_instance, task
- erp-message: message, message_subscription

Update DTOs to expose version in responses and require version in update
requests. HTTP 409 Conflict returned on version mismatch.

crates/erp-message/src/service/subscription_service.rs

@@ -5,6 +5,7 @@ use uuid::Uuid;
 use crate::dto::{MessageSubscriptionResp, UpdateSubscriptionReq};
 use crate::entity::message_subscription;
 use crate::error::{MessageError, MessageResult};
+use erp_core::error::check_version;
 
 /// 消息订阅偏好服务。
 pub struct SubscriptionService;
@@ -46,6 +47,9 @@ impl SubscriptionService {
         let now = Utc::now();
 
         if let Some(model) = existing {
+            let current_version = model.version;
+            let next_ver = check_version(req.version, current_version)
+                .map_err(|_| MessageError::VersionMismatch)?;
             let mut active: message_subscription::ActiveModel = model.into();
             if let Some(types) = &req.notification_types {
                 active.notification_types = Set(Some(types.clone()));
@@ -64,6 +68,7 @@ impl SubscriptionService {
             }
             active.updated_at = Set(now);
             active.updated_by = Set(user_id);
+            active.version = Set(next_ver);
 
             let updated = active
                 .update(db)
@@ -112,6 +117,7 @@ impl SubscriptionService {
             dnd_end: m.dnd_end.clone(),
             created_at: m.created_at,
             updated_at: m.updated_at,
+            version: m.version,
         }
     }
 }