…slice 9) (pnpm#521)

Enables `nodeLinker: hoisted` for multi-importer (workspace) lockfiles.
Previously the hoister rejected any lockfile with importers beyond `.`
with `UnsupportedWorkspace`; now the whole workspace shares one hoist
plan so conflicting versions across projects dedupe, and each
importer's project-tree node_modules is materialized per-project.

real-hoist:
- Drop the upfront UnsupportedWorkspace guard in `hoist()`. The
  wrapper already constructed non-root importers as Workspace-kind
  children of the virtual `.` root; only the guard needed to go.
- Add `HoistOpts::hoist_workspace_packages: bool` (default true).
  When false, non-root importers stay out of the shared tree
  (matches upstream's `hoistWorkspacePackages: false` mode for the
  Bit CLI). Removed the corresponding error variant.

hoisted_dep_graph walker:
- Replace the `workspace:`-prefix skip with a recurse-into branch:
  for each Workspace-kind hoister child, walk its post-hoist
  children under `<lockfile_dir>/<importer_id>/node_modules`. The
  workspace node itself is NOT added to the graph or to the
  parent's hierarchy — it has no contents to import.
- Add per-importer `hierarchy` and `direct_dependencies_by_importer_id`
  entries. Per-importer direct deps are computed from the lockfile
  (not from the workspace node's post-hoist children) because
  hoisted-up siblings don't show up in the workspace node's tree.
  First-recorded location wins, matching upstream's
  `pkgLocationsByDepPath[depPath][0]` pick.
- Add `LockfileToHoistedDepGraphOptions::hoist_workspace_packages`
  (default true) and plumb to HoistOpts.

Config:
- Add `Config::hoist_workspace_packages: bool` (#[default = true]).
  Read from `pnpm-workspace.yaml` via `WorkspaceSettings`.

SymlinkDirectDependencies:
- Add `link_only: bool` flag. When true, skip every Regular dep and
  only materialize Link entries (workspace siblings). Used by the
  hoisted branch in InstallFrozenLockfile::run so workspace-sibling
  symlinks land under each importer's `node_modules/<alias>` even
  though the regular deps now live as real directories from the
  hoisted linker.

InstallFrozenLockfile::run:
- Plumb `config.hoist_workspace_packages` into the walker.
- After link_hoisted_modules, run SymlinkDirectDependencies with
  `link_only: true` so workspace siblings get their per-project
  symlinks. Mirrors upstream's hoisted branch at
  https://github.com/pnpm/pnpm/blob/94240bc046/installing/deps-restorer/src/index.ts#L411-L440.

Tests:
- real-hoist: replace the now-removed `UnsupportedWorkspace` test
  with one that pins multi-importer hoister output (Workspace
  children with percent-encoded names + `workspace:<id>` references)
  and one that pins the `hoist_workspace_packages: false` opt-out.
- walker: three new tests cover per-importer direct_deps emission,
  per-importer hierarchy entries, the `hoist_workspace_packages: false`
  root-only mode, and version-conflict-across-importers nesting.

…slice 9) (pnpm#521)

Enables `nodeLinker: hoisted` for multi-importer (workspace) lockfiles.
Previously the hoister rejected any lockfile with importers beyond `.`
with `UnsupportedWorkspace`; now the whole workspace shares one hoist
plan so conflicting versions across projects dedupe, and each
importer's project-tree node_modules is materialized per-project.

real-hoist:
- Drop the upfront UnsupportedWorkspace guard in `hoist()`. The
  wrapper already constructed non-root importers as Workspace-kind
  children of the virtual `.` root; only the guard needed to go.
- Add `HoistOpts::hoist_workspace_packages: bool` (default true).
  When false, non-root importers stay out of the shared tree
  (matches upstream's `hoistWorkspacePackages: false` mode for the
  Bit CLI). Removed the corresponding error variant.

hoisted_dep_graph walker:
- Replace the `workspace:`-prefix skip with a recurse-into branch:
  for each Workspace-kind hoister child, walk its post-hoist
  children under `<lockfile_dir>/<importer_id>/node_modules`. The
  workspace node itself is NOT added to the graph or to the
  parent's hierarchy — it has no contents to import.
- Add per-importer `hierarchy` and `direct_dependencies_by_importer_id`
  entries. Per-importer direct deps are computed from the lockfile
  (not from the workspace node's post-hoist children) because
  hoisted-up siblings don't show up in the workspace node's tree.
  First-recorded location wins, matching upstream's
  `pkgLocationsByDepPath[depPath][0]` pick.
- Add `LockfileToHoistedDepGraphOptions::hoist_workspace_packages`
  (default true) and plumb to HoistOpts.

Config:
- Add `Config::hoist_workspace_packages: bool` (#[default = true]).
  Read from `pnpm-workspace.yaml` via `WorkspaceSettings`.

SymlinkDirectDependencies:
- Add `link_only: bool` flag. When true, skip every Regular dep and
  only materialize Link entries (workspace siblings). Used by the
  hoisted branch in InstallFrozenLockfile::run so workspace-sibling
  symlinks land under each importer's `node_modules/<alias>` even
  though the regular deps now live as real directories from the
  hoisted linker.

InstallFrozenLockfile::run:
- Plumb `config.hoist_workspace_packages` into the walker.
- After link_hoisted_modules, run SymlinkDirectDependencies with
  `link_only: true` so workspace siblings get their per-project
  symlinks. Mirrors upstream's hoisted branch at
  https://github.com/pnpm/pnpm/blob/94240bc046/installing/deps-restorer/src/index.ts#L411-L440.

Tests:
- real-hoist: replace the now-removed `UnsupportedWorkspace` test
  with one that pins multi-importer hoister output (Workspace
  children with percent-encoded names + `workspace:<id>` references)
  and one that pins the `hoist_workspace_packages: false` opt-out.
- walker: three new tests cover per-importer direct_deps emission,
  per-importer hierarchy entries, the `hoist_workspace_packages: false`
  root-only mode, and version-conflict-across-importers nesting.