`enableRouteGeneration: false` also disables `autoCodeSplitting`

Which project does this relate to?

Router

Describe the bug

When using the Vite plugin, if you set enableRouteGeneration: false (for instance if you don't want to generate routes when building since they shouldn't be changing) and autoCodeSplitting: true, then it won't automatically code split the built version.

Your Example Website or App

N/A

Steps to Reproduce the Bug or Issue

1. Set enableRouteGeneration: false and autoCodeSplitting: true
2. Build the application and routes won't be split automatically, you need to use .lazy

Expected behavior

I expect to have automatic code splitting regardless of what is set for enableRouteGeneration

Screenshots or Videos

No response

Platform

• Router / Start Version: 1.131.35
• OS: Windows
• Browser: N/A
• Browser Version: N/A
• Bundler: Vite
• Bundler Version: 7.1.4

Additional context

No response

Start at the Vite plugin entry point where enableRouteGeneration and autoCodeSplitting are handled. Reproduce the issue with route generation disabled and automatic code splitting enabled, then build the application. Done means automatic code splitting still occurs without requiring .lazy.