`read()` has inconsistent results when run in `run` vs. `preview`

Describe the bug

When calling read() in a Remote function which is using an aliased route:

read("$data/myFile.txt");

where data is a directory called "data" in the root of the project.

read() results in the following error: Error: Asset does not exist: data/myFile.txt when running npm run preview but fetches the file without issue when run in the dev server.

Whether you define an alias in svelte.config.js or not doesn't appear to make any difference.

It's worth noting that trying to fetch the file with fs.readFileSync also doesn't appear to work

Reproduction

https://stackblitz.com/edit/sveltejs-kit-template-default-jr3n9eow?file=src%2Froutes%2Ffetch.remote.ts

Had to reproduce since the problem actually exists when running npm run build rather than npm run dev, but the setup to recreate it is in that link.

Logs

System Info

System:
    OS: Linux 6.16 EndeavourOS
    CPU: (16) x64 AMD Ryzen 7 7800X3D 8-Core Processor
    Memory: 15.90 GB / 30.45 GB
    Container: Yes
    Shell: 5.9 - /usr/bin/zsh
  Binaries:
    Node: 24.8.0 - /usr/bin/node
    npm: 11.6.0 - /usr/bin/npm
    pnpm: 10.16.1 - /usr/bin/pnpm
  npmPackages:
    @sveltejs/adapter-auto: ^6.0.0 => 6.1.0
    @sveltejs/adapter-node: ^5.3.2 => 5.3.2
    @sveltejs/kit: ^2.22.0 => 2.38.1
    @sveltejs/vite-plugin-svelte: ^6.0.0 => 6.2.0
    svelte: ^5.0.0 => 5.38.10
    vite: ^7.0.4 => 7.1.5

Severity

blocking an upgrade

Additional Information

There's a good chance there is another workaround for this, but even after having asked in the Discord I'm not able to find one.

This is blocking me from being able to consistently read files from the server using the new Remote functions.

Start with the linked reproduction and its src/routes/fetch.remote.ts entry point, then compare npm run dev with npm run build and npm run preview. Check the related svelte.config.js alias setup and verify that read("$data/myFile.txt") resolves the same file in both modes.