dev-container-maintenance

Modify, audit, troubleshoot, and maintain the VS Code Dev Container setup for Open Mercato. MUST use this skill for ANY change to .devcontainer/ files — it contains the file map, update procedures, and mandatory documentation requirements. Use when: (1) adding or changing anything in the dev container (new system packages, new services, version bumps, Dockerfile edits, env var changes, port changes), (2) the dev container fails to build or start, (3) services inside the container misbehave (wrong versions, connection errors, missing env vars), (4) the regular project setup changed and the dev container needs to match, (5) a user reports "works locally but not in dev container", (6) periodic maintenance audit. Triggers on any mention of "dev container", "devcontainer", ".devcontainer", "container setup", "container Dockerfile", "add to container", "install in container", "update dev container", "container broken", "container not working".