fix(cli): install plugin scaffold dev dependencies

[galligan]

Summary

• make bb plugin new --app explicitly include development dependencies in its npm install
• add a regression test that runs the scaffold command under NODE_ENV=production and records the npm arguments through a fake executable

Root cause

The packaged CLI inherits NODE_ENV=production. The scaffold stores required build and type packages in devDependencies, but the CLI launched plain npm install. npm therefore omitted those packages while exiting successfully, so the CLI reported that dependencies were installed even though the new plugin could not build.

Passing --include=dev makes the CLI-owned install independent of the parent process environment.

User impact

A successful bb plugin new <name> --app dependency installation now leaves the generated plugin ready for bb plugin build without a second manual install.

Validation

• pnpm exec turbo run test --filter=@bb/cli --force — 369 tests passed
• pnpm exec turbo run typecheck --filter=@bb/cli
• pnpm exec prettier --check apps/cli/src/__tests__/plugin-new.test.ts
• git diff --check

Fixes #1133