Navigating with `reloadDocument: true` broken with basepath in RC

[jakst]

Which project does this relate to?

Start

Describe the bug

If you have set up a basepath and have a navigation with reloadDocument: true, the navigation will not include the basepath.

Your Example Website or App

https://github.com/jakst/tanstack-start-basepath-reload-document

Steps to Reproduce the Bug or Issue

1. Clone the repo and install dependencies with pnpm install
2. Launch the dev server with pnpm dev
3. Visit the app on http://localhost:3000/app
4. Click the button button to navigate to /about with reloadDocument: true
5. Notice the app navigated to /about instead of /app/about and that an error message was thrown

Note: the basepath handling seems to work properly when navigating back from /app/about to /.

Expected behavior

I expect navigations with reloadDocument: true to respect basepath

Screenshots or Videos

No response

Platform

• Router / Start Version: 1.132.43
• OS: MacOS
• Browser: Chrome
• Browser Version: 140
• Bundler: vite
• Bundler Version: 7.1.9

Additional context

No response