[BUG] `npm ls` flags installed optional peers as extraneous under `install-strategy=linked`

Is there an existing issue for this?

• I have searched the existing issues

This issue exists in the latest npm version

• I am using the latest npm

This is not just a request to bump a dependency for a CVE

• This is not solely a request to bump a dependency for a CVE

Current Behavior

With install-strategy=linked, a satisfied optional peer is symlinked into the dependent's own node_modules, and npm ls reports that symlink as extraneous. It affects workspaces and store packages alike (seen in a large monorepo on every workspace with an optional @types/react peer). Hoisted is clean, and it started in npm 11.6.3 (11.6.2 is clean).

Expected Behavior

An installed optional peer that the dependent resolves is not extraneous, matching hoisted.

Steps To Reproduce

mkdir x && cd x
mkdir -p packages/a
printf '{"name":"r","version":"1.0.0","workspaces":["packages/*"],"dependencies":{"a":"1.0.0","ws":"8.21.3","utf-8-validate":"6.0.5"}}' > package.json
printf '{"name":"a","version":"1.0.0","peerDependencies":{"utf-8-validate":"^6"},"peerDependenciesMeta":{"utf-8-validate":{"optional":true}}}' > packages/a/package.json
printf 'install-strategy=linked\n' > .npmrc
npm install --ignore-scripts --no-audit --no-fund
npm ls --all
# actual: utf-8-validate@6.0.5 extraneous under both a@1.0.0 and ws@8.21.3
# expected: no extraneous (same as --install-strategy=hoisted)

Environment

• npm: 12.0.2 and latest source
• Node.js: v24.18.0
• OS Name: macOS Darwin 25.6.0
• npm config: install-strategy=linked

Start by running the provided workspace reproduction with npm install --install-strategy=linked and npm ls --all, then compare its output with hoisted installation. Trace how npm ls classifies the symlinked optional peer under the dependent and workspace packages; done means a satisfied optional peer is no longer reported as extraneous in both cases.