setupFiles doesn't respect custom `ssr.resolve.conditions`

Describe the bug

When using setupFiles, it doesn't respect custom ssr.resolve.conditions from the vite.config.ts to add monorepo-local setup files from packages. I'd originally asked about this in https://github.com/vitest-dev/vitest/discussions/9353, but I was looking into it again and I noticed that it looks like this worked when https://github.com/vitest-dev/vitest/issues/6992 was filed/fixed, so I'm refiling as a regression.

Reproduction

https://stackblitz.com/edit/vitest-dev-vitest-6hyfbf3b?file=vite.config.ts

To demonstrate this is a resolution bug: in packages/project-b/package.json, set the default export condition to point at the .ts file instead of the .js file to fix it (which, however, isn't an option for us, however, because project-b is published to npm).

System Info

System:
    OS: macOS 26.2
    CPU: (10) arm64 Apple M4
    Memory: 204.11 MB / 24.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 24.12.0 - /Users/dukese01/.local/share/mise/installs/node/24.12.0/bin/node
    npm: 11.6.2 - /Users/dukese01/.local/share/mise/installs/node/24.12.0/bin/npm
    pnpm: 10.26.0 - /Users/dukese01/.local/share/mise/installs/node/24.12.0/bin/pnpm
    Deno: 2.6.4 - /opt/homebrew/bin/deno
    Watchman: 2026.01.05.00 - /opt/homebrew/bin/watchman
  Browsers:
    Chrome: 143.0.7499.170
    Safari: 26.2
  npmPackages:
    @vitest/eslint-plugin: 1.6.1 => 1.6.1 
    vitest: 4.0.15 => 4.0.15

Used Package Manager

pnpm

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

Start with the StackBlitz reproduction and inspect vite.config.ts alongside packages/project-b/package.json, especially the export conditions and the setupFiles configuration. Trace how the custom ssr.resolve.conditions are applied during setup-file resolution; done means the monorepo-local TypeScript setup file resolves under the custom conditions without requiring the package's default condition to change.