[LaPaGaYo]

Summary

• Adds durable GitHub Issues sync foundation: schema/projections, links, comments, operation tracking, and project-level settings.
• Imports and reconciles GitHub issues with conflict-aware title/body/state handling, issue and issue_comment webhooks, and worker backfill.
• Surfaces engineering controls plus inbound GitHub issue/comment context in the UI, while keeping comments inbound-only for Phase 14.

Verification

• npm run lint
• npm run typecheck
• npm test
• npm run build
• git diff --check
• Browser smoke: engineering issue sync controls visible; detail GitHub issue card/comment visible; external comment has no edit/delete controls.