In continuation of our exploration of using `install-strategy=linked` in
the [Gutenberg
monorepo](WordPress/gutenberg#75814), which
powers the WordPress Block Editor.

When using `install-strategy=linked`, npm overrides for transitive
dependencies were ignored.
The overridden version was installed but reported as `invalid` instead
of `overridden`, and with `strict-peer-deps` the install failed entirely
with `ERESOLVE`.

The root cause is that override propagation stops at Link nodes and
never reaches their targets.
Overrides propagate through the tree via `addEdgeIn` ->
`updateOverridesEdgeInAdded` -> `recalculateOutEdgesOverrides`.
When a Link node receives overrides, `recalculateOutEdgesOverrides`
iterates over `this.edgesOut` — but Links have no `edgesOut` (their
targets do).
So overrides never reach the target node's dependency edges, and those
edges use `rawSpec` instead of the overridden spec.

In the linked strategy, all packages in `node_modules/` are Links
pointing to targets in `.store/`.
This meant no overrides propagated past the first level of the
dependency tree.

The fix overrides `recalculateOutEdgesOverrides` in the `Link` class to
forward overrides to the target node.
When `buildIdealTree` creates a root Link (e.g. on macOS where `/tmp` ->
`/private/tmp`), the target Node is now created with `loadOverrides:
true` so it loads override rules from `package.json`.

The `#applyRootOverridesToWorkspaces` workaround method is removed — it
was compensating for this exact bug by detaching workspace edges whose
specs didn't match. With proper propagation, workspace edges already
have the correct overridden spec, making the workaround dead code.

## References

Fixes #9197

(cherry picked from commit bc32d94)

In continuation of our exploration of using `install-strategy=linked` in
the [Gutenberg
monorepo](WordPress/gutenberg#75814), which
powers the WordPress Block Editor.

When using `install-strategy=linked`, npm overrides for transitive
dependencies were ignored.
The overridden version was installed but reported as `invalid` instead
of `overridden`, and with `strict-peer-deps` the install failed entirely
with `ERESOLVE`.

The root cause is that override propagation stops at Link nodes and
never reaches their targets.
Overrides propagate through the tree via `addEdgeIn` ->
`updateOverridesEdgeInAdded` -> `recalculateOutEdgesOverrides`.
When a Link node receives overrides, `recalculateOutEdgesOverrides`
iterates over `this.edgesOut` — but Links have no `edgesOut` (their
targets do).
So overrides never reach the target node's dependency edges, and those
edges use `rawSpec` instead of the overridden spec.

In the linked strategy, all packages in `node_modules/` are Links
pointing to targets in `.store/`.
This meant no overrides propagated past the first level of the
dependency tree.

The fix overrides `recalculateOutEdgesOverrides` in the `Link` class to
forward overrides to the target node.
When `buildIdealTree` creates a root Link (e.g. on macOS where `/tmp` ->
`/private/tmp`), the target Node is now created with `loadOverrides:
true` so it loads override rules from `package.json`.

The `#applyRootOverridesToWorkspaces` workaround method is removed — it
was compensating for this exact bug by detaching workspace edges whose
specs didn't match. With proper propagation, workspace edges already
have the correct overridden spec, making the workaround dead code.


## References

Fixes #9197

In continuation of our exploration of using `install-strategy=linked` in
the [Gutenberg
monorepo](WordPress/gutenberg#75814), which
powers the WordPress Block Editor.

When using `install-strategy=linked`, npm overrides for transitive
dependencies were ignored.
The overridden version was installed but reported as `invalid` instead
of `overridden`, and with `strict-peer-deps` the install failed entirely
with `ERESOLVE`.

The root cause is that override propagation stops at Link nodes and
never reaches their targets.
Overrides propagate through the tree via `addEdgeIn` ->
`updateOverridesEdgeInAdded` -> `recalculateOutEdgesOverrides`.
When a Link node receives overrides, `recalculateOutEdgesOverrides`
iterates over `this.edgesOut` — but Links have no `edgesOut` (their
targets do).
So overrides never reach the target node's dependency edges, and those
edges use `rawSpec` instead of the overridden spec.

In the linked strategy, all packages in `node_modules/` are Links
pointing to targets in `.store/`.
This meant no overrides propagated past the first level of the
dependency tree.

The fix overrides `recalculateOutEdgesOverrides` in the `Link` class to
forward overrides to the target node.
When `buildIdealTree` creates a root Link (e.g. on macOS where `/tmp` ->
`/private/tmp`), the target Node is now created with `loadOverrides:
true` so it loads override rules from `package.json`.

The `#applyRootOverridesToWorkspaces` workaround method is removed — it
was compensating for this exact bug by detaching workspace edges whose
specs didn't match. With proper propagation, workspace edges already
have the correct overridden spec, making the workaround dead code.

## References

Fixes #9197

(cherry picked from commit bc32d94)