fix(pm): reject filtered add and remove on Yarn Classic

[jong-kyung]

Summary

Yarn Classic currently receives yarn workspaces foreach for filtered add/remove commands, but it does not support foreach and fails with Invalid subcommand.

Reject --filter with a clear error on Yarn Classic while preserving the existing Yarn Berry behavior. This also covers vp install <packages> --filter and Classic remove calls combining --filter with --recursive.

Reference

• https://classic.yarnpkg.com/en/docs/cli/workspaces
• https://yarnpkg.com/cli/workspaces/foreach

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-15T03:42:28.203821Z	480b1e7	Manual request

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[fengmk2]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Bravo.

Reviewed commit: 480b1e7626

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