Adds a short Egress section to the README explaining that agent
containers route HTTP through a per-agent pipelock sidecar on a Docker
--internal network, what the baked-in default allowlist covers, and
how to extend it via bottles.<name>.egress.allowlist with a single
JSON example. Points readers at PRD 0001 and the pipelock assessment
note for the full design and rationale.
Refs: docs/prds/0001-per-agent-egress-proxy-via-pipelock.md
Assisted-by: Claude Code
didericis