[mode777]

What & why

PSflix has no user-facing documentation. This adds a maintained docs site for players — covering sign-in, browsing/favorites, playing in the browser, save states, memory cards, and environment-specific troubleshooting (cross-origin isolation, the known Chromium audio quirk) — and publishes it automatically to GitHub Pages.

Part of the add-user-docs-site OpenSpec change (planning artifacts included).

What's in it

• user-docs/ — self-contained VitePress 1.6.4 project (own package.json/package-lock, root install untouched), Obsidian Console dark-only branding (Inter, #121414 bg, PS-blue/teal brand ramp), local search, 7 content sections
• .github/workflows/docs.yml — builds on PRs touching user-docs/**; on master pushes composes the Pages artifact with docs under docs/ (site root reserved for the future landing page) and deploys via deploy-pages. workflow_dispatch supported for first deploy
• Config touches: user-docs added to ESLint ignores; VitePress dist/cache gitignored. No app code changes
• openspec: planning artifacts for the change + archive of the previously completed docker-release-pipeline change

How to test

1. CI docs build check passes on this PR (deploy job is skipped on PRs)
2. Root gates unaffected: npm run lint && npm run typecheck (Node 20, per CI)
3. After merge: Pages deploys and https://mode777.github.io/psflix/docs/ serves the branded site; deep links and search work
4. Repo Pages source is already set to "GitHub Actions"