Goal

Bump package.json engines.node from >=18.0.0 → >=20.0.0 and update the docs references to match.

Why this is a separate issue from #523

#523 catches the symptom (OIDC IdP 500s on Node 18 due to Array#toReversed and crypto.hash in oidc-provider). The disposition there is "defer until Node 18 fades naturally" — see the disposition comment on #523. This issue tracks the bookkeeping work to update our advertised runtime so the docs stop lying-by-omission.

Why not now

• Node 18 reached EOL April 2025 — user base shrinking on its own.
• nodejs-mobile users have a working downstream-patch path on Node 18 today.
• Bumping now would warn (not block) Node 18 installs — small disruption for diminishing returns.

When to act

Pick one of these triggers, whichever comes first:

• A new user hits OIDC IdP 500s on Node <20: @koa/router (via oidc-provider) uses Array#toReversed #523 (i.e., the natural fade slowed enough that we're getting fresh reports).
• An annual sweep of engines fields, after Node 20 itself approaches EOL (April 2026 currently scheduled).
• Tied to a JSS major version bump (e.g., 0.1.0).

Scope when picked up

Refs

• OIDC IdP 500s on Node <20: @koa/router (via oidc-provider) uses Array#toReversed #523 — the original symptom + why we're deferring
• Mobile: run JSS on Android via React Native + nodejs-mobile (PoC + portability findings) #522 — Android (nodejs-mobile) work, which keeps the Node 18 patch path alive