Fix existing ESLint failures - #5

Summary

• fix the existing ESLint failure in FarmCanvas by scheduling RAF redraws through a ref-backed helper
• move render-time ref writes into effects or event callbacks
• replace legacy game-state migration any casts with a narrowed legacy cell type

Verification

• npm run lint
• npm run build
• git diff --check HEAD^ HEAD

Notes

• This PR only addresses the existing lint failures. It does not change the global shortcut behavior, licensing, or dependencies.