Support kubectl config

[jxs1211]

I want to propose a feature for supporting kubectl config operations and would like to contribute the feature.

➜  mcp-server-kubernetes git:(main) ✗ k config --help
Modify kubeconfig files using subcommands like "kubectl config set current-context my-context"

 The loading order follows these rules:

  1.  If the --kubeconfig flag is set, then only that file is loaded. The flag may only be set once and no merging takes place.
  2.  If $KUBECONFIG environment variable is set, then it is used as a list of paths (normal path delimiting rules for your system). These paths are merged. When a value is modified, it is modified in the file that defines the stanza. When a value is created, it is created in the first file that exists. If no files in the chain exist, then it creates the last file in the list.
  3.  Otherwise, ${HOME}/.kube/config is used and no merging takes place.

Available Commands:
  current-context Display the current-context
  delete-cluster  Delete the specified cluster from the kubeconfig
  delete-context  Delete the specified context from the kubeconfig
  delete-user     Delete the specified user from the kubeconfig
  get-clusters    Display clusters defined in the kubeconfig
  get-contexts    Describe one or many contexts
  get-users       Display users defined in the kubeconfig
  rename-context  Rename a context from the kubeconfig file
  set             Set an individual value in a kubeconfig file
  set-cluster     Set a cluster entry in kubeconfig
  set-context     Set a context entry in kubeconfig
  set-credentials Set a user entry in kubeconfig
  unset           Unset an individual value in a kubeconfig file
  use-context     Set the current-context in a kubeconfig file
  view            Display merged kubeconfig settings or a specified kubeconfig file

Usage:
  kubectl config SUBCOMMAND [options]

Use "kubectl <command> --help" for more information about a given command.
Use "kubectl options" for a list of global command-line options (applies to all commands).

[Flux159]

This would need extensive testing and updates to https://github.com/Flux159/mcp-server-kubernetes/blob/main/src/utils/kubernetes-manager.ts to support changing the kubectl config / contexts. I think some new changeContext function would need to reset everything that is set in the constructor, then expose that to the llm via a tool. There's also probably some nuance around what state we're tracking in kubernetes-manager - if we want to properly clear things across multiple contexts.

Most tools use k8sManager.getCoreApi, etc. and we would need to make sure that those work correctly after a config or context change.

You may also face this issue, but as long as it's documented that config changes will not work with the same username due to a caching issue in the client dependency that should be fine.

[Flux159]

As mentioned in #97 (comment) - there may be an api that supports this in the javascript client which would make it a bit easier to implement.

[Flux159]

We now have list contexts, set context, and get context tool calls in v1.4.0.

Note that we're not supporting every kube config operation - @jxs1211 are there other operations than the ones I listed that you want to add or should this be closed?