chore(skills): keep marketing toolkit local

[ericyangpan]

Summary

• remove the marketing toolkit and skills-lock.json from the repository tree while retaining the local installation
• remove the redundant project copies of skill-creator for Codex and Claude
• remove the marketing-only CSpell dictionary entry
• retain the four project-owned skills under .agents/skills

Why

The marketing toolkit is workstation-local tooling and should not be published in the GitHub repository. Codex and Claude already provide built-in skill creation support, so the checked-in copies are redundant.

Impact

After merge, the marketing toolkit, lock file, and bundled skill-creator directories will no longer appear in the latest main Files tree. Local marketing skills remain available through the repository-local Git exclude configuration.

Validation

• npm run format:check
• npm run biome:check
• npm run test:ci
• CSpell against the 913 files tracked by the Git index
• git diff --cached --check before each commit

[github-actions]

Preview deployment

Status	URL
Ready	https://pr-175-aicodingstack.pr-preview.workers.dev

Commit: 161b06d
Updated: 2026-07-29T15:48:57.593Z

[github-actions]

Preview deployment cleaned up

The preview deployment for PR #175 has been removed.