fix: resolve 4 bugs in termui - #3715

Process completed with exit code 1.

@termuijs/dev-server#build: command (/home/runner/work/TermUI/TermUI/packages/dev-server) /home/runner/.bun/bin/bun run build exited (1)

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/