swamp-extension-publish skill: add quality rubric check before push

Problem

The swamp-extension-publish skill's 8-state checklist runs formatting (state 6) and a dry-run (state 7) before pushing, but it never runs a quality rubric check. Quality failures are only discovered after the fact — or not at all — unless the user manually runs the check themselves.

During a recent publish session, the skill completed all 8 states and pushed successfully, but the published extension had quality rubric failures that were never surfaced during the publish flow.

Proposed Solution

Add a new state between state 6 (formatted) and state 7 (dry_run_passed) — call it quality_checked:

State 6.5: quality_checked

swamp extension quality manifest.yaml --json

• If the command reports failures, block the push and display the failures to the user with guidance to fix them.
• If the command reports warnings (but no failures), surface them and ask the user to confirm before proceeding.
• If the command passes, continue to dry-run as normal.

This mirrors how swamp extension fmt --check gates the formatting state — the quality check should be an equal gate before any publish.

Alternatives Considered

• Running quality check after push (too late — the version is already public)
• Making it optional/skippable (acceptable, but it should be opt-out, not opt-in)