fe9d05664c
Make the cred-proxy a per-bottle sidecar container on the bottle's internal docker network instead of a root-owned process inside the agent container. The boundary becomes container namespace separation, matching pipelock and git-gate. Update summary, problem, goals, in-scope, architecture diagram, components, existing code touched, external deps, and open questions; add a "Considered alternatives" section recording the rejected in-container shape.