Node CI Bump

[BrainInBlack]

What & why

CI, Node version bump to 24 LTS

Type of change

• Bug fix
• New feature
• Documentation only
• Refactor / cleanup (no behavior change)

Checklist

• One focused change, with a short description of the why (above).
• Targets the develop branch (or main for an urgent fix).
• Type-check is clean: npx tsc --noEmit.
• Tests pass: npm test — and new behavior is covered by a test where practical.
• Both builds succeed: npm run build.
• Added a note under ## [Unreleased] in CHANGELOG.md.
• If behavior changed, kept the docs in sync: README.md, docs/ARCHITECTURE.md, and any in-app help.
• No secrets, no telemetry, and data still stays local to the browser.

Testing