Make Lit copy-spec cross-platform

[RobinsonBeato]

Summary

The Lit renderer build currently relies on mkdir -p and cp, which fail on Windows. This replaces that step with a small Node script so npm run build works cross-platform.

Changes

• Replace the copy-spec command with a Node script.
• Add scripts/copy-spec.mjs to copy spec JSON files into src/0.8/schemas.

Why this matters

Windows contributors currently hit a hard build failure during copy-spec. This makes the build portable across OSes without changing outputs.

Testing

• cd renderers/lit
• npm install
• npm run build
• • Tested on Windows (PowerShell)