Add Taskfile wrappers for skill publish workflows #46

Outcome

Expose Aether's existing deterministic distribution and gh skill publish workflow through the repository's standard Taskfile command surface without making Taskfile the canonical implementation.

Scope

• Add a root Taskfile.yml composition entrypoint.
• Add focused skill/release tasks rather than embedding release logic in the composition root.
• Provide a safe skills:publish:dry-run wrapper around gh skill publish "dist" --dry-run.
• Provide an explicit tagged skills:publish wrapper that requires a release tag and runs the dry-run path before publication.
• Delegate distribution generation to the existing ./aether distribution build command.
• Keep CI/release workflows able to invoke the underlying commands directly.
• Fail clearly when gh or Task prerequisites are unavailable; never embed credentials.

Acceptance criteria

• task skills:publish:dry-run builds the distribution and performs the GitHub CLI publish dry-run.
• task skills:publish RELEASE_TAG=<tag> requires an explicit tag and performs validation before publication.
• The Taskfile contains no release secret/token values.
• Underlying Aether/GitHub CLI commands remain canonical and independently runnable.
• Documentation shows the Taskfile convenience commands and their direct-command equivalents.

Related

• Build the first-party AI artifact validation and publishing pipeline #38 — first-party AI artifact validation and publishing pipeline
• Implement provider-neutral projections and GitHub MCP configuration #39 — provider-neutral projections

Non-goals

• Automatically publishing on merge.
• Replacing the protected GitHub Actions release workflow.
• Hiding GitHub CLI behavior behind bespoke release logic.