Helm 4 compatibility

[tsacha]

Summary

• helm list: drop the -a flag removed in Helm 4
• helm status: drop --show-desc, removed in helm/helm#13444; default status output still includes the release description.
• helm get manifest: pass -n <namespace> so the correct release is used when the same name exists in several namespaces.

Details

This PR adds Helm v4 compatibility and fixes a Lua error triggered when fetching releases:

Error executing vim.schedule lua callback: ...y/kubectl.nvim/lua/kubectl/resources/helm/definition.lua:10: bad argument #1 to 'ipairs' (table expected, got string)
stack traceback:
        [C]: in function 'ipairs'
        ...y/kubectl.nvim/lua/kubectl/resources/helm/definition.lua:10: in function 'processFunc'
        .../nvim/lazy/kubectl.nvim/lua/kubectl/resource_factory.lua:76: in function 'process'
        ...im/lazy/kubectl.nvim/lua/kubectl/resources/helm/init.lua:69: in function <...im/lazy/kubectl.nvim/lua/kubectl/resources/helm/init.lua:68>

Helm v4 deleted -a / --all flag from the list command:

$ helm version
version.BuildInfo{Version:"v4.1.3", GitCommit:"c94d381b03be117e7e57908edbf642104e00eb8f", GitTreeState:"", GoVersion:"go1.26.1-X:nodwarf5", KubeClientVersion:"v1.35"}
$ helm ls -a -A --output json
Error: unknown shorthand flag: 'a' in -a

An upstream PR (helm/helm#31828) aims to reintroduce it for backward compatibility, but it hasn't been merged yet.

Note on breaking changes:

This update changes how kubectl.nvim behaves with Helm v3: superseded, uninstalled, pending-install, and pending-upgrade releases will no longer be displayed in the list.

To maintain the previous behavior across both versions, we could use explicit flags: --pending --deployed --failed --superseded --uninstalled --uninstalling. Let me know if you'd like me to update the PR to maintain full backward compatibility.

[Ramilito]

Hey! Awesome work!

I do want to stay backwards compatible with v3 somehow.
I suggest we do it in a simple manner by just adding a helm configuration option, what do you think? Alternatively we could dynamically figure out the version and store it when going to the helm view.

[tsacha]

There you go. I tried the second solution with a sync shell command. The version is cached in M.version after the first call, so helm version is only executed once per session.

[Ramilito]

Don't we want the namespace here?