`enableRouteGeneration: false` also disables `autoCodeSplitting`

[high-risc]

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