feat(kubernetes): Guard kubectl initialization and completions

Ensures kubectl-related aliases and functions are only sourced if the `kubectl` command is available.

bashrc_overrides/kubernetes

@@ -1,7 +1,8 @@
-source <(kubectl completion bash)
-alias k="kubectl"
-alias kcontext="kubectl config use-context"
-kns() {
+if command -v kubectl >/dev/null 2>&1; then
+  source <(kubectl completion bash)
+  alias k="kubectl"
+  alias kcontext="kubectl config use-context"
+  kns() {
     if [[ $# -eq 0 ]]; then
       printf '%s\n' "$(kubectl config view --minify -o jsonpath='{.contexts[0].context.namespace}')"
     else
@@ -9,17 +10,18 @@ kns() {
       kubectl config set-context --current --namespace "$ns"
       printf 'Switched current context to namespace: %s\n' "$ns"
     fi
-}
-_kns_completion() {
+  }
+  _kns_completion() {
     local cur
     cur=${COMP_WORDS[COMP_CWORD]}
     COMPREPLY=( $(compgen -W "$(kubectl get namespaces -o name | sed 's|namespace/||')" -- "$cur") )
-}
-_kcontext_completion() {
+  }
+  _kcontext_completion() {
     local cur
     cur=${COMP_WORDS[COMP_CWORD]}
     COMPREPLY=( $(compgen -W "$(kubectl config get-contexts -o name)" -- $cur) )
-}
-complete -F __start_kubectl k
-complete -F _kns_completion kns
-complete -F _kcontext_completion kcontext
+  }
+  complete -F __start_kubectl k
+  complete -F _kns_completion kns
+  complete -F _kcontext_completion kcontext
+fi