Publish PRD issues with native GitHub relationships #468

Parent

#455

What to build

Make PRD publication create or resume GitHub-native parent, sub-issue, and blocked-by relationships without treating local .claude/epics files or the legacy gh-sub-issue extension as authoritative. Keep publication separate from lifecycle commands so each contract can be merged and rolled back independently.

Acceptance criteria

• Publication creates or resumes one parent issue and the expected child issues with the exact approved category and triage labels.
• Parent/sub-issue and blocked-by relationships use GitHub's native APIs and are read back before success is reported.
• Each run uses a genuinely fresh scratch root; no stale mapping from an earlier run can satisfy the current publication.
• A partial failure is duplicate-safe: retry resumes existing published issues instead of creating another parent or duplicate children.
• Parallel publication verifies the expected mapping count, unique issue numbers, and one mapping for every source task before relationship readback or source rename.
• The initialization path verifies the required native gh capabilities without installing or requiring gh-sub-issue.
• One focused publication check covers fresh publication, partial-failure resume, incomplete or duplicate mappings, and a missing local epic mirror.
• git diff --check passes.

Blocked by

#456 defines the lifecycle contract and terminology.

Out of scope

• Issue show, status, close, reopen, and sync behavior; that remains Mutate issue lifecycle from GitHub without a local mirror #457.
• Historical issue migration, branch protection, runtime deployment, or trading behavior.
• Broad removal of unrelated legacy PM commands.