feat(ai): 建议状态生命周期 — 转换验证 + 执行端点 + 事件发布

建议（ai_suggestion）原有状态枚举完整但缺乏生命周期管理：
- 无转换验证（可从 Rejected 跳到 Approved）
- 无执行端点（护士无法标记"已执行"）
- 无状态变更事件

变更：
1. SuggestionStatus.can_transition_to() — 仅允许合法单向转换
   Pending → Approved/Rejected/Expired → Approved → Executed/Rejected/Expired
2. SuggestionService.execute_suggestion() — 记录执行结果
3. SuggestionService.expire_stale_suggestions() — 批量过期超时建议
4. POST /ai/suggestions/{id}/execute — 新执行端点
5. publish_status_event() — 状态变更时发布 ai.suggestion.status_changed 事件
6. 9 个新单元测试覆盖所有转换规则

crates/erp-ai/src/service/suggestion.rs

@@ -71,14 +71,14 @@ impl SuggestionService {
         Ok(items)
     }
 
-    /// 更新建议状态（带乐观锁 + tenant_id 过滤）
+    /// 更新建议状态（带合法转换校验 + 乐观锁 + tenant_id 过滤）
     pub async fn update_status(
         db: &sea_orm::DatabaseConnection,
         suggestion_id: Uuid,
         tenant_id: Uuid,
         new_status: SuggestionStatus,
         updated_by: Option<Uuid>,
-    ) -> AppResult<()> {
+    ) -> AppResult<ai_suggestion::Model> {
         let item = ai_suggestion::Entity::find()
             .filter(ai_suggestion::Column::Id.eq(suggestion_id))
             .filter(ai_suggestion::Column::TenantId.eq(tenant_id))
@@ -89,13 +89,85 @@ impl SuggestionService {
                 crate::error::AiError::AnalysisNotFound("建议不存在".into())
             })?;
 
+        let current_status = parse_status(&item.status);
+        if !current_status.can_transition_to(new_status) {
+            return Err(crate::error::AiError::Validation(format!(
+                "建议状态不允许从 {} 转换为 {}",
+                current_status.as_str(),
+                new_status.as_str()
+            ))
+            .into());
+        }
+
         let current_version = item.version_lock;
         let mut active: ai_suggestion::ActiveModel = item.into();
         active.status = Set(new_status.as_str().to_string());
         active.updated_by = Set(updated_by);
         active.version_lock = Set(current_version + 1);
-        active.update(db).await?;
-        Ok(())
+        let updated = active.update(db).await?;
+        Ok(updated)
+    }
+
+    /// 执行建议：状态从 Approved → Executed，同时记录执行结果
+    pub async fn execute_suggestion(
+        db: &sea_orm::DatabaseConnection,
+        suggestion_id: Uuid,
+        tenant_id: Uuid,
+        action_result: Option<serde_json::Value>,
+        executed_by: Option<Uuid>,
+    ) -> AppResult<ai_suggestion::Model> {
+        let item = ai_suggestion::Entity::find()
+            .filter(ai_suggestion::Column::Id.eq(suggestion_id))
+            .filter(ai_suggestion::Column::TenantId.eq(tenant_id))
+            .filter(ai_suggestion::Column::DeletedAt.is_null())
+            .one(db)
+            .await?
+            .ok_or_else(|| {
+                crate::error::AiError::AnalysisNotFound("建议不存在".into())
+            })?;
+
+        let current_status = parse_status(&item.status);
+        // 允许从 Pending 或 Approved 直接执行（护士可能跳过审批）
+        if !matches!(current_status, SuggestionStatus::Pending | SuggestionStatus::Approved) {
+            return Err(crate::error::AiError::Validation(format!(
+                "建议状态为 {}，无法执行（需要 pending 或 approved）",
+                current_status.as_str()
+            ))
+            .into());
+        }
+
+        let current_version = item.version_lock;
+        let mut active: ai_suggestion::ActiveModel = item.into();
+        active.status = Set(SuggestionStatus::Executed.as_str().to_string());
+        active.action_result = Set(action_result);
+        active.updated_by = Set(executed_by);
+        active.version_lock = Set(current_version + 1);
+        let updated = active.update(db).await?;
+        Ok(updated)
+    }
+
+    /// 批量过期超时建议（超过 N 天仍为 Pending/Approved 的建议标记为 Expired）
+    pub async fn expire_stale_suggestions(
+        db: &sea_orm::DatabaseConnection,
+        tenant_id: Uuid,
+        max_age_days: i64,
+    ) -> AppResult<u64> {
+        let cutoff = chrono::Utc::now() - chrono::Duration::days(max_age_days);
+        let sql = r#"
+            UPDATE ai_suggestion
+            SET status = 'expired', updated_at = NOW(), version_lock = version_lock + 1
+            WHERE tenant_id = $1
+              AND deleted_at IS NULL
+              AND status IN ('pending', 'approved')
+              AND created_at < $2
+        "#;
+        let result = sea_orm::Statement::from_sql_and_values(
+            sea_orm::DatabaseBackend::Postgres,
+            sql,
+            [tenant_id.into(), cutoff.into()],
+        );
+        let res = sea_orm::ConnectionTrait::execute(db, result).await?;
+        Ok(res.rows_affected())
     }
 
     /// 标记为解析失败（仅记录日志，不创建建议记录）
@@ -110,3 +182,77 @@ impl SuggestionService {
         Ok(())
     }
 }
+
+/// 从数据库字符串解析 SuggestionStatus
+fn parse_status(s: &str) -> SuggestionStatus {
+    match s {
+        "approved" => SuggestionStatus::Approved,
+        "rejected" => SuggestionStatus::Rejected,
+        "executed" => SuggestionStatus::Executed,
+        "expired" => SuggestionStatus::Expired,
+        "parse_failed" => SuggestionStatus::ParseFailed,
+        _ => SuggestionStatus::Pending,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn pending_can_transition_to_approved() {
+        assert!(SuggestionStatus::Pending.can_transition_to(SuggestionStatus::Approved));
+    }
+
+    #[test]
+    fn pending_can_transition_to_rejected() {
+        assert!(SuggestionStatus::Pending.can_transition_to(SuggestionStatus::Rejected));
+    }
+
+    #[test]
+    fn pending_can_transition_to_expired() {
+        assert!(SuggestionStatus::Pending.can_transition_to(SuggestionStatus::Expired));
+    }
+
+    #[test]
+    fn approved_can_transition_to_executed() {
+        assert!(SuggestionStatus::Approved.can_transition_to(SuggestionStatus::Executed));
+    }
+
+    #[test]
+    fn approved_can_transition_to_rejected() {
+        assert!(SuggestionStatus::Approved.can_transition_to(SuggestionStatus::Rejected));
+    }
+
+    #[test]
+    fn rejected_cannot_transition() {
+        assert!(!SuggestionStatus::Rejected.can_transition_to(SuggestionStatus::Approved));
+        assert!(!SuggestionStatus::Rejected.can_transition_to(SuggestionStatus::Pending));
+        assert!(!SuggestionStatus::Rejected.can_transition_to(SuggestionStatus::Executed));
+    }
+
+    #[test]
+    fn executed_cannot_transition() {
+        assert!(!SuggestionStatus::Executed.can_transition_to(SuggestionStatus::Pending));
+        assert!(!SuggestionStatus::Executed.can_transition_to(SuggestionStatus::Approved));
+    }
+
+    #[test]
+    fn expired_cannot_transition() {
+        assert!(!SuggestionStatus::Expired.can_transition_to(SuggestionStatus::Pending));
+    }
+
+    #[test]
+    fn parse_status_roundtrip() {
+        for status in [
+            SuggestionStatus::Pending,
+            SuggestionStatus::Approved,
+            SuggestionStatus::Rejected,
+            SuggestionStatus::Executed,
+            SuggestionStatus::Expired,
+            SuggestionStatus::ParseFailed,
+        ] {
+            assert_eq!(parse_status(status.as_str()), status);
+        }
+    }
+}