LSP loads vite.config.ts with the server's cwd as root #3217

Describe the bug

oxlint/oxfmt load vite.config.ts without a root (apps/shared/src-js/vite_plus_config.ts):

resolveConfig({ configFile: path }, "build")

Vite falls back to process.cwd(). In a multi-root workspace (oxc-project/oxc-vscode#418) that's another repo, so plugins resolve against it. TanStack Start fails:

Could not resolve entry for router entry: router in app-a/src

The failing project is plain Vite (no vite-plus), so lazyPlugins() from #1756 isn't available.

Fix: resolveConfig({ root: dirname(path), configFile: path }, "build").

Reproduction

No repo. Steps below.

Steps to reproduce

1. Workspace with a Vite+ repo first, then a Vite + TanStack Start repo.
2. Open in VS Code with the Oxc extension.
3. Loading the second repo's config fails.

System Info

vp v1.3.0 (vite 8.3.4, oxlint 1.88.0, oxfmt 0.73.0)
Node 24.22.1, bun 1.4.4, macOS 27.0.1
Oxc VS Code 1.64.1

Used Package Manager

bun

Logs

Failed to load config: app-c/vite.config.ts
Error: Could not resolve entry for router entry: router in app-a/src
    at resolveEntry (@tanstack/start-plugin-core/dist/esm/resolve-entries.js:30:45)
    at BasicMinimalPluginContext.config (@tanstack/start-plugin-core/dist/esm/vite/plugin.js:55:29)
    at runConfigHook (app-a/.../@voidzero-dev/vite-plus-core/dist/vite/node/chunks/...)

Validations

• Read the Contributing Guidelines.
• Check that there isn't already an issue for the same bug.
• Confirm this is a Vite+ issue and not an upstream issue (Vite, Vitest, tsdown, Rolldown, or Oxc).
• The provided reproduction is a minimal reproducible example.