chore: remove website/ in favor of postguard-docs

[dobby-coder]

Summary

Removes the in-repo Docusaurus documentation site. Its content has been fully consolidated into the centralized docs repo at docs.postguard.eu (encryption4all/postguard-docs), and the repo README already links there.

Closes #135.

What is removed

• website/ — Docusaurus source (7 docs pages, homepage, config, generated lockfile, static assets)
• .github/workflows/docs.yml — the GitHub Pages deploy workflow that built and published website/ on every push to main
• # Docusaurus entries in .gitignore

Coverage check

Before removing, I verified every page under website/docs/ has equivalent (or more complete) content in postguard-docs:

Removed page	Covered in postguard-docs
intro.md	guide/what-is-postguard.md, guide/concepts.md, repos/postguard.md
getting-started.md	repos/postguard.md (prerequisites, build, dev env, env vars, CLI usage)
architecture/overview.md	guide/architecture.md, guide/protocol.md
architecture/encryption-flow.md	guide/architecture.md (encryption + decryption flows), guide/protocol.md (identity derivation algorithm, multi-recipient KEM)
architecture/yivi-integration.md	guide/concepts.md (Yivi), repos/postguard.md (sender/recipient flows, hidden policies, API key auth)
api/pkg-server.md	repos/postguard.md (PKG Server API), guide/architecture.md (API Endpoints)
api/wasm-bindings.md	repos/postguard.md (WASM Bindings + wire format)

postguard-docs also covers the pg-ffi crate, which was missing from the in-repo site.

Side effects

• Two open dependabot PRs target /website (chore(deps): bump follow-redirects from 1.15.11 to 1.16.0 in /website #131 follow-redirects, chore(deps): bump dompurify from 3.3.3 to 3.4.0 in /website #132 dompurify). They will become obsolete and dependabot will close them automatically after this merges.
• The encryption4all.github.io/postguard/ GitHub Pages site will stop being updated by this repo. Consider adding a redirect or taking the page down separately.

Test plan

• Confirmed no other files in the repo reference website/ (only docs.yml and .gitignore, both updated)
• Confirmed Cargo.toml workspace members do not include website
• Root README already points to docs.postguard.eu
• CI (build + PR title checks) passes after push

[dobby-coder]

Dobby is most grateful to Master rubenhensen for the approval! 🧦 Dobby sees his PR has been approved and merged — Dobby is honored! Dobby will now check if there are any loose ends to tidy up from this change.

[dobby-coder]

All follow-up items from this PR are resolved:

• Issue Delete website folder #135 — closed automatically by the merge
• Dependabot PR chore(deps): bump follow-redirects from 1.15.11 to 1.16.0 in /website #131 (follow-redirects) — auto-closed (target directory removed)
• Dependabot PR chore(deps): bump dompurify from 3.3.3 to 3.4.0 in /website #132 (dompurify) — auto-closed (target directory removed)
• CI — all checks passed before merge

Remaining follow-up (for maintainers): The old GitHub Pages site at encryption4all.github.io/postguard/ will go stale now that the docs.yml workflow is removed. Consider adding a redirect to docs.postguard.eu or disabling Pages for this repo.

Thanks @rubenhensen for the review and merge!