Track domain-specific Git and GitHub effect adapters

[flyingrobots]

Roadmap C outcome

Add Git and GitHub external-action profiles only after the workspace effect boundary and Graft consumer are proven.

Required decomposition before implementation

Create one owning-repository issue per operation family, with independent authority, idempotency, reconciliation, and settlement law:

• CreateFeatureBranch;
• CreateCommitFromExplicitPaths;
• PushFeatureRef;
• OpenPullRequest;
• ObservePullRequestChecks;
• ObserveReviewThreads; and
• MergeGatedPullRequest.

Raw shell, arbitrary Git argv, force push, direct main push, ambient network, and administrative merge are not operation identities.

Dependency

Blocked by #12. The native edge is maintained through GraphQL.

Non-goals

• implementation before Roadmap B closes;
• model judgment adapter;
• autonomous delivery-loop orchestration.