fix(arborist): omit root dev deps in linked strategy when shared with workspaces

[manzoorwanijk]

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

Summary

Fixes --omit=dev (and --omit=optional, --omit=peer) not being fully respected in the linked install strategy for monorepos.

PR #9066 added a shouldOmit() check during graph traversal in makeIdealGraph(), which works for dev deps that are only dev deps. However, it missed two cases:

• Shared external packages: When a root devDependency is also a workspace prodDependency, the node has dev=false (reachable via prod paths), so shouldOmit() returns false. The package correctly goes into the store (the workspace needs it), but root incorrectly gets a symlink to it because #assignCommonProperties() doesn't filter by edge type.
• Workspace dev deps: Workspaces listed in root's devDependencies are always hoisted to root's node_modules/ because #rootDeclaredDeps unconditionally includes devDependencies keys, and npm auto-creates workspace type edges (not dev edges) for all workspaces.

Changes

1. Filter edges by type in #assignCommonProperties() for root and workspace nodes — dev, optional, and peer edges are excluded when their corresponding --omit flag is set.
2. Exclude omitted dep types from #rootDeclaredDeps — so workspaces declared only as root devDependencies aren't hoisted when --omit=dev is set.

References

Fixes #9080