Support starting TiDB cluster managed by K8s and tidb-operator in case that K8s itself has a full cluster crash

Feature Request

Is your feature request related to a problem? Please describe:

In some extreme scenarios, Kubernetes cluster and services may crash unexpected due to bugs or intended mis-operations.
In that case, tidb cluster pods managed by K8s may not work normally, which lead to business failure. If we want to recover from failure, we need to locate and fix problem which may consume a lot of time.

Describe the feature you'd like:

TiUP support fetching topology metadata of tidb cluster from tidb-operator and regularly updating local repository. When K8s service is unavailable, TiUP can read cluster metadata from local to restart the affected tidb cluster.

Describe alternatives you've considered:

Deploy another tidb cluster separately as an active standy cluster in advance or use BR backup to restore data to a new cluster after a failure.

Teachability, Documentation, Adoption, Migration Strategy:

Start by reading the TiUP repository and the linked tidb-operator project to understand how TiDB cluster topology metadata is currently managed. Define the metadata-fetching, local-update, and Kubernetes-outage recovery entry points before identifying what tests and recovery behavior would demonstrate completion.