composer.lock and vendor/composer/installed.json record each package's
"dist.url" as the store path of the build-time composer-repository
mirror, which drags that whole ~570MB fixed-output derivation into the
runtime closure even though it's just install provenance -- neither
Laravel's package manifest (name/extra only) nor Composer's runtime
InstalledVersions (reads installed.php, not this file) consult it.
Cuts the package closure from ~1.75GB to ~1.18GB.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>