Add FileSystem-based router plugin by default when frontend build is needed

[mshabarov]

Describe your motivation

Hilla's FS-based router plugin is supposed to be added by hand:

• run "npm i @vaadin/hilla-file-router" (should be double checked, because Hilla might make this already)
• add the "vitePluginFileSystemRouter" Vite plugin into vite.config.ts:

       const customConfig: UserConfigFn = (env) => ({
          plugins: [vitePluginFileSystemRouter()]
       });

This would also trigger a file views.js that is needed for routes.tsx.

We can start by adding this plugin always and investigate possible impact on Flow users.
Then we can consider adding it only when Hilla is used.

Describe the solution you'd like

Flow adds this plugin into generated Vite config and adds it's package to package.json.

Additional context

Vaadin 24.4.

[knoobie]

This should be done by default, so whenever Flow starts the frontend build (Vite dev server or new bundle build), the plugin is installed and applied.

Only if Hilla is used, right? :)

[mshabarov]

Well, yes. Not needed for bundle and basically when Hilla not used. Let me correct.

[vaadin-bot]

This ticket/PR has been released with Vaadin 24.4.0.