fix: 审批拒绝不发通知，仅保留创建/审批通过/执行结果三个通知点

backend/app/api/v1/endpoints/ticket.py

@@ -670,15 +670,15 @@ async def review_ticket(
     await db.commit()
     await db.refresh(ticket)
 
-    # 发送审批通知
-    try:
-        event_type = "ticket_approved" if data.action == "approve" else "ticket_rejected"
-        await _send_ticket_notification(db, ticket, event_type, {
-            "approver": current_user.display_name,
-            "comment": data.comment or ("审批通过" if data.action == "approve" else "审批拒绝"),
-        })
-    except Exception as notify_err:
-        logger.error("审批通知发送失败: %s", notify_err)
+    # 发送审批通知（仅审批通过时通知，拒绝不通知）
+    if data.action == "approve":
+        try:
+            await _send_ticket_notification(db, ticket, "ticket_approved", {
+                "approver": current_user.display_name,
+                "comment": data.comment or "审批通过",
+            })
+        except Exception as notify_err:
+            logger.error("审批通知发送失败: %s", notify_err)
 
     return await _enrich_ticket(ticket, db)