feat(runners): add the B300 DSXE cluster and retire the B300 NV launcher / 添加 B300 DSXE 集群并下线 B300 NV 启动脚本 - #2826

Bugbot Analysis Progress (4m 52s elapsed)

✅ Gathered PR context (5s)
✅ Completed bug detection (4m 45s)
✅ Posted analysis results (3s)

Final Result: Bugbot completed review - no new issues found. 1 previously reported issue remain unresolved.

Request ID: serverGenReqId_770e5964-588f-452e-8f70-7692f9cf538f