[Feature] Add handlers for kubectl exec/config, git checkout/switch, glab, uv run

Summary

Across 30 days of data engineering work (38,377 Bash commands tracked via rtk discover), top patterns rtk doesn't handle account for ~250-300K tokens/week of missed savings.

Top unhandled patterns

Pattern	Count/30d	Example	Suggested handler
kubectl exec POD -- cmd	907	kubectl exec -n database postgres-0 -- psql ...	Filter exec output (similar to existing rtk kubectl logs)
kubectl config <subcmd>	190	kubectl config get-contexts	Filter context list output
git checkout <branch>	439	git checkout dev	Add to rtk git handlers
git switch <branch>	(subset)	git switch dev	Same — add to rtk git
glab ci view / glab mr create	290	glab ci view 1412676	New rtk glab handler (similar to rtk gh)
uv run <script>	127	uv run --isolated pytest tests/	New rtk uv handler (similar to rtk pip)

Bonus: kubectl flag-before-subcommand pattern

The largest miss class is kubectl --context X -n NS <subcommand> and kubectl -n NS <subcommand>. The matcher only catches kubectl <subcommand> [flags]. Could the matcher be enhanced to recognize flag-before patterns for output filtering purposes? This would recover thousands of commands per week per heavy user.

Why this matters

Heavy users in DevOps / data engineering contexts hit these patterns continuously. Even with behavioral guidance (telling the assistant to put flags AFTER subcommand), kubectl exec and glab simply have no rtk handler today.

Volunteer

Happy to help test new handlers if useful.