Run workspace tooling on Bun except Cloudflare's

The repository ran its own scripts on both Bun and Node, with formatting through Prettier. Formatting now goes through bun fmt (Prettier remains only for the marketing site’s .astro files), and lint, repository checks, workspace and release tests, builds, generators, recovery commands and the macOS packaging scripts run on Bun. In the packaging scripts, jq replaces two node -e JSON readers.

The local stack and backend scripts, the device test runner, the Vitest suites that run beside workerd, and the sandbox image stay on Node because Wrangler, workerd and miniflare run on it. scripts/README.md records what runs where.