Ordinary plugins now show exported icons, and subpath plugins use
<subpath>/icon instead of a package.json. Update the display checklist
and nested-package gate cases to match.
Manifest icon diagnostics name the package.json the author edits.
verify-package-meta rejects a package.json export that resolves to build
output instead of reading it, and PackageManifest.exports uses a narrow
export-target type.
Subpath plugins are not packages, so they never read a package.json and
take their icon from the exported <specifier>/icon resource, like locale.
Package roots keep manifest text fallback and icon, with ./icon as the
fallback image. Drop the bundle-only reader option.
Yif