Platform engineer trail

Goal: make ACORN repeatable across repositories, services, and local inference tools.

1. Define sources and defaults with ACORN configuration.
2. Aggregate versioned buckets with download.
3. Follow the model workflow from metadata import through weight selection.
4. Route downloaded models to applications with sync.
5. Use serve for supported GitLab bot automation, distribute acorn skill for compatible agents, and keep doctor nearby as the rescue guide. MCP paths are listed by the CLI but are not yet implemented.

For CI commands that support it, use global --offline mode when the job must be deterministic and ensure every required network-backed asset is cached or configured explicitly. Commands reject offline mode when they cannot honor that guarantee.

Next stop: Define the workflow in ACORN configuration.