[codex] Add advisory workflow, artifacts, and GitHub marketing plan

[timharris707]

Summary

• Add the durable workflow kit and advisory UI/artifact batch.
• Reposition the public README around Panely as an AI advisory board for broad life, work, product, creative, investment, and technical decisions.
• Clarify the three session modes separately from model/provider choices.
• Add concrete artifact examples for the Full Artifact, Decision Memo, Action Plan, Risk Memo, and Board Brief.
• Remove the obsolete hosted-SaaS landing-page draft with unsupported pricing, free-session, testimonial, share-link, model-provider, and SOC 2 claims.
• Add the reviewed docs/plans/github-marketing.md plan, plus generated HTML/tracker views, for the remaining GitHub polish: screenshots, sanitized fixtures, examples, metadata, trust copy, claim/proof checks, and the v0.9.x public-consumption candidate path.

Verification

• npm run verify
• scripts/render_plan --check docs/plans/github-marketing.md
• workflow/bin/review.sh approved the staged plan diff with no blocking findings