PrimeReact not usable when building a SPA with react-router

Describe the bug

I tried to build a simple SPA app using react-router (using the Framwork mode) and PrimeReact as UI component library.
Dev-Mode (run npm dev) runs just fine but building for production returns the following error:

> react-router-prime-react@1.0.0 build
> react-router build

vite v6.3.5 building for production...
✓ 52 modules transformed.
build/client/.vite/manifest.json                  1.46 kB │ gzip:  0.38 kB
build/client/assets/root-DMeMvrIX.css             0.02 kB │ gzip:  0.04 kB
build/client/assets/root-4yxUZWD5.js              0.90 kB │ gzip:  0.53 kB
build/client/assets/index-HSk3ZO2X.js             3.95 kB │ gzip:  1.55 kB
build/client/assets/api.esm-BaowmBN3.js           6.14 kB │ gzip:  2.57 kB
build/client/assets/home-DSQmwM_l.js             88.17 kB │ gzip: 22.86 kB
build/client/assets/chunk-PVWAREVJ-D513GI-F.js  112.89 kB │ gzip: 38.07 kB
build/client/assets/entry.client-Lv1_BQlD.js    182.76 kB │ gzip: 58.25 kB
✓ built in 1.42s
vite v6.3.5 building SSR bundle for production...
✓ 5 modules transformed.
build/server/.vite/manifest.json               0.23 kB
build/server/assets/server-build-DMeMvrIX.css  0.02 kB
build/server/index.js                          5.99 kB

✓ 1 asset cleaned from React Router server build.
build\server\assets\server-build-DMeMvrIX.css

✗ Build failed in 71ms
[react-router] Directory import 'D:\react-router_primeReact\node_modules\primereact\utils' is not supported resolving ES modules imported from D:\react-router_primeReact\node_modules\primereact\api\api.esm.js
Did you mean to import "primereact/utils/utils.cjs.js"?
    at finalizeResolution (node:internal/modules/esm/resolve:263:11)
    at moduleResolve (node:internal/modules/esm/resolve:932:10)
    at defaultResolve (node:internal/modules/esm/resolve:1056:11)
    at ModuleLoader.defaultResolve (node:internal/modules/esm/loader:654:12)
    at ModuleLoader.#cachedDefaultResolve (node:internal/modules/esm/loader:603:25)
    at ModuleLoader.resolve (node:internal/modules/esm/loader:586:38)
    at ModuleLoader.getModuleJobForImport (node:internal/modules/esm/loader:242:38)
    at ModuleJob._link (node:internal/modules/esm/module_job:135:49) {
  code: 'PLUGIN_ERROR',
  url: 'file:///D:/react-router_primeReact/node_modules/primereact/utils',
  pluginCode: 'ERR_UNSUPPORTED_DIR_IMPORT',
  plugin: 'react-router',
  hook: 'writeBundle'
}

PrimeReact appears to use non conformant directory imports.

See also: https://github.com/remix-run/react-router/issues/14350

Reproducer

https://github.com/ferdi-github/react-router_primeReact

System Information

System:
    OS: Windows 11 10.0.26100
    CPU: (16) x64 AMD Ryzen 7 PRO 6850U with Radeon Graphics     
    Memory: 6.88 GB / 30.77 GB
  Binaries:
    Node: 22.13.1 - C:\Program Files\nodejs\node.EXE
    npm: 9.8.0 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Chromium (140.0.3485.54)
  npmPackages:
    @react-router/dev: 7.8.2 => 7.8.2 
    @react-router/node: 7.8.2 => 7.8.2 
    react-router: 7.8.2 => 7.8.2 
    vite: ^6.3.3 => 6.3.5

Steps to reproduce the behavior

1. Create minimal app with react-router and PrimeReact
2. Configure react-router.config.tsto emit a SPA (no SSR)
3. Use at least PrimeReactProvider
4. Run npm run build
5. Build error

Expected behavior

Protuction build should run successfully.

Start with the linked reproducer, react-router.config.ts, and the failing import reported in node_modules/primereact/api/api.esm.js. Run npm run build with the listed React Router and PrimeReact setup, then trace how the primereact/utils import is resolved during the production build. Done means the minimal SPA production build completes successfully.