Supered v0.6.0

Public Codex marketplace release.\n\nHighlights:\n- Added a public Codex marketplace manifest at .agents/plugins/marketplace.json.\n- Added a public Codex plugin bundle at plugins/supered.\n- Added npm run verify-codex-plugin for manifest, marketplace, mirror, docs, assets, and skills drift checks.\n- Documented public install: codex plugin marketplace add fhajjej-ship-it/Supered --ref main && codex plugin add supered@supered.\n\nVerification passed:\n- npm test\n- npm run validate\n- npm run smoke-install\n- npm run verify-package\n- npm run verify-codex-plugin\n- npm run verify-site\n- npm audit --audit-level=high\n- clean-temp Codex install from GitHub marketplace