Add inertia:start-ssr and inertia:stop-ssr artisan commands

[reinink]

This PR adds two new Inertia artisan commands for starting and stopping the Inertia SSR server:

# start the SSR server
php artisan inertia:start-ssr

# stop the SSR server
php artisan inertia:stop-ssr

The goal here is to simplify the SSR setup, removing the need to add these commands to your package.json scripts.

  "scripts": {
    "dev": "vite",
    "build": "vite build && vite build --ssr",
-   "ssr:serve": "node bootstrap/ssr/ssr.mjs",
-   "ssr:shutdown": "[ $(curl -s 'http://localhost:13714/shutdown'; echo $?) -eq 52 ]"
  },

This update includes a new inertia.ssr.bundle config option. This is the path to your local Inertia SSR bundle. By default it's set to base_path('bootstrap/ssr/ssr.mjs'), which is where the Laravel Vite plugin puts it, but you can change it to another location if needed. For example, if you're using webpack it might be located at public_path('js/ssr.js').

As part of this update I also changed the inertia.ssr.url config value to not require the /render endpoint as part of the URL, as I'm now using this URL for both rendering and shutting down. I've made this change in a backwards compatible way — meaning if your config still includes /render in the URL, we automatically strip it out.