Portable operating guidance migration

This bundle carries provider-neutral workflow guidance into Compass’s existing skills and rules. The management-tree model, async channel/topic communication, and operator merge gate remain authoritative.

The migration reviewed the source guidance and deliberately omitted flat-peer coordination and its transport, provider-specific credentials and commands, and provider-specific infrastructure and merge policy. The exclusions frozen by DL-143 remain unchanged; adding an exclusion requires a separate decision.

Extension points are the configured issue and review tools, the CI-engine hooks in a later skill bundle, and user configuration for infrastructure providers. The portable skills define behavior and evidence requirements without selecting an adapter.

Issue lifecycle guidance remains in own-your-issue.md; the dedicated skill is deferred under BC-3 until its issue and PR tools are available. The ownership rule stays behavioral and names no unavailable tool.