chore: error guide pages for GitHub Pages

[MarkAlex1234]

Summary

docs/
├── _config.yml           Jekyll (primer theme, seo-tag, sitemap) for GitHub Pages at /docs
├── index.md              migration guide + checklist + links
└── errors/
    ├── eneedauth.md          "npm error code ENEEDAUTH with trusted publishing"
    ├── e404-put.md           "npm error 404 Not Found - PUT https://registry.npmjs.org"
    ├── e422-repository-url.md
    ├── still-uses-token.md
    └── bypass-2fa-notice.md  "npm notice npm tokens that bypass 2FA are being restricted"

Each page is titled with the exact error string people paste into search. It gives the cause, the fix, and npx go-tokenless as the automated path. Research counted 82 open issues mentioning ENEEDAUTH with trusted publishing and 140 mentioning a trusted-publisher E404. The README troubleshooting section and llms.txt link the pages.

After merge, Pages is enabled with source main and /docs.

Merge danger

Door: two-way

Blast radius: docs only.

[claude]

Docs-only change. Links, relative paths and the docs/assets/header.png reference resolve, and the Jekyll config is consistent with the /go-tokenless base URL. No blocking issues.

I couldn't build the Pages site or check the cited npm deadlines and versions (January 2027, npm@^12). Please confirm those before merge.