Feature request: add rtk rewrite for `docker exec`

Context

rtk discover --all shows docker exec as the #1 unhandled command across our sessions:

• 1,953 invocations in the last 30 days
• Typical usage: docker exec <container> nginx -s reload, docker exec <container> alembic upgrade head, etc.

Request

Add an RTK rewrite/filter for docker exec output to reduce token usage. The output of commands run inside containers is often verbose (full stack traces, log dumps, env dumps) and could benefit from RTK's filtering.

Example commands

docker exec oysi_static nginx -s reload
docker exec pricing_api alembic upgrade head
docker exec <container> env

Found via rtk discover --all.