Make network configuration a mandatory menu selection

[Softer]

• This fix issue:

PR Description:

Users frequently forget to configure network during installation, resulting in no internet after reboot. And I think there are not many setups without a network :)

This PR makes the network selection item mandatory (same pattern as Disk configuration). Users must explicitly choose one of the options before Install becomes available.

A new "No network" option is added for users who intentionally want no network on the target system.

The network options list follows the enum order instead of alphabetical sorting, with "No network" at the bottom.

A recommendation hint is shown in the menu header.

Tests and Checks

• Network not selected -> Install shows "Missing configurations: Network configuration"
• Select any network option -> Install unblocked
• Select "No network" -> Install unblocked, no network packages installed
• Old config with network_config via --config -> works as before
• Old config without network_config -> mandatory prompt in interactive mode

[svartkanin]

I'm not sure this is a good argument, users should not be forced into selections that are not required for an installation.
Right now only the required settings for a working system are required and this deviates from that pattern.

[Softer]

I agree with the principle of minimalism, but I think that in 2026, the network, in most cases, meets the minimum requirements.

[svartkanin]

Considering there is a fair amount of people installing it on VMs and such it may still be somewhat impactfull

[Softer]

In any case, we are not forcing the user but helping them not to forget to configure (or not configure) the network. They either consciously choose “No network” or do not forget to set it up and will not end up with a system without a network after installation.

[svartkanin]

@Torxed what's your thoughts on it?

[Torxed]

I don't wish this to be forced. Main reason being the tool should be versatile. Especially the main menu items are not to be enforced IMHO. Some desktop stuff, maybe? But even then, I've prepared laptops that are intended to be used without networking..

So I believe the argument for this is weaker than the intention. It's also perfectly possibly to configure systemd-networkd post-install if you forgot networking. It's 1-2 text files with 5-10 lines and you're up and running :)

[Softer]

We're not forcing the user to configure the network or making it mandatory. Especially if they don't need it - that's exactly what the "No network" option is for :) Same pattern as Disk configuration - the user just needs to make a conscious choice.

What about a non-blocking warning instead? Show a note in the Install preview when network is not configured, but don't block the installation.

[Torxed]

We're not forcing the user to configure the network

I must have misunderstood something, I'll re-read when I get back to a computer.