fix(cli): use the Rust workspace lookup for the monorepo root

[liangmiQwQ]

Inspired by voidzero-dev/vite-task#859

The JS findWorkspaceRoot in resolve-vite-config.ts was a second copy of vt_workspace::find_workspace_root, the lookup that vp run and vp install use. The two copies had drifted apart:

• The JS copy treated lerna.json as a monorepo root. The rest of vp does not.
• The JS copy could not parse a package.json saved with a UTF-8 BOM, so it skipped that root and kept walking up.
• The JS copy skipped any malformed package.json and kept walking up, so it could return an unrelated workspace above the real one.

This PR adds a findMonorepoRoot binding. It wraps find_workspace_root and returns the root only for pnpm and package.json workspaces. vp pack (resolveViteConfig with traverseUp) and vp create (getConfiguredCreate) now use it, and the JS copy is removed. A malformed package.json now throws the same error both commands already hit in their earlier Rust lookup.

This PR also fixes findViteConfigUp. It checked its start directory before checking that the directory was inside the stop directory. Running vp pack at a monorepo root with no vite.config could pick up a config from the directory above the root.

🤖 Generated with Claude Code

[fengmk2]

@codex review

[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 2026-10-18T05:10:47.365906Z	bfdea4c	Manual request

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[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Delightful!

Reviewed commit: bfdea4ca69

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