fix(arborist): load transitive optional deps into linked actual tree

[manzoorwanijk]

In continuation of our exploration of using install-strategy=linked in the Gutenberg monorepo, which powers the WordPress Block Editor.

Under install-strategy=linked, an installed transitive optional dependency was missing from the actual tree built by loadActual when scanning the filesystem (forceActual: true), the path npm sbom and npm query use. On disk the dep is correct — extracted in .store and symlinked as a store sibling of its consumer — but npm sbom omitted it (e.g. chokidar → fsevents: 14 components vs the hoisted strategy's 15; esbuild → @esbuild/darwin-arm64 likewise).

In #findMissingEdges(), the skip condition treated an edge as already resolved when !edge.missing. An unresolved optional edge has no target yet reports missing === false (Edge.error returns null for an optional edge with no target), so it was skipped and the on-disk store sibling was never walked or loaded.

This changes the check to walk any edge whose target is unresolved, including optional ones. The walk only loads a package that actually exists in an ancestor node_modules, so genuinely-uninstalled optionals (impossible platform) stay absent, and behavior is unchanged for required, missing, dummy, and hoisted-ancestor edges. The linked SBOM now matches the hoisted strategy.

References

Fixes #9627

[github-actions]

🎉 Backport to release/v11 created: #9665