kubectl rewrite misses --context flag, exec subcommand, and variable assignments

Problem

rtk discover shows ~1,300 kubectl commands not being rewritten despite kubectl being a supported proxy. The issue is that rtk rewrite only handles the simplest form (kubectl <subcommand> ...) but misses common real-world patterns.

Patterns not rewritten

Pattern	Example	Expected
Flags before subcommand	kubectl --context msquant-test get pods -n test	rtk kubectl --context msquant-test get pods -n test
kubectl exec	kubectl exec -n test pod-0 -- psql	rtk kubectl exec -n test pod-0 -- psql
Variable assignment wrapper	REDIS_POD=$(kubectl get pods -n test -l app=redis -o name)	REDIS_POD=$(rtk kubectl get pods ...)
Line continuation	\kubectl --kubeconfig ...	rtk kubectl --kubeconfig ...

Reproduction

$ rtk rewrite 'kubectl get pods -n test'
rtk kubectl get pods -n test          # ✅ works

$ rtk rewrite 'kubectl --context msquant-test get pods -n test'
# exit 1, no output                   # ❌ missed

$ rtk rewrite 'kubectl exec -n test msquant-postgresql-0 -- psql'
# exit 1, no output                   # ❌ missed

$ rtk rewrite 'REDIS_POD=$(kubectl get pods -n test -l app=redis -o name)'
# exit 1, no output                   # ❌ missed

Environment

• rtk 0.30.1
• macOS (Darwin 23.5.0)
• Hook: rtk-rewrite.sh (hook v2)

Impact

~1,300 kubectl commands over 30 days not getting token savings. kubectl output (pod lists, describe, logs) is often very verbose — high savings potential.