Leave Wi-Fi to NetworkManager when archinstall turned on iwd as well

archinstall's "Copy ISO network configuration", which a user who connected
with iwctl may pick, turns on iwd and systemd-networkd. CoreDesktop then
turns on NetworkManager too, and after a restart two services fight over
the Wi-Fi card. system/wifi.sh disables iwd and systemd-networkd, without
stopping them, when NetworkManager is enabled and isn't set to use iwd
itself. install.sh runs it, and a migration runs it on existing machines.
The README tells users to choose NetworkManager in archinstall.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -28,6 +28,7 @@ These scripts are based on the initial work of [Typecraft](https://www.youtube.c
 (Note: if you're on a laptop and/or don't have a wired internet connection, set up Wi-Fi first. See "A Note About Networking in Arch" below.)
 
 4) You will go through the different options. Mostly choose the defaults.
+   - At "Network configuration", choose "Use NetworkManager", even if you connected with `iwctl`. CoreDesktop uses NetworkManager, and GNOME's Wi-Fi menu needs it. "Copy ISO network configuration" turns on iwd instead, which fights NetworkManager over the Wi-Fi card; CoreDesktop turns iwd off if it finds it (see "Notes about what is installed").
 5) Video cards: IF YOU HAVE AN NVIDIA GPU, CHOOSE THE PROPRIETARY NVIDIA OPTION. Choose the AMD option for AMD cards. Just works better. We've found Arch is very good at maintaining compatibility with Nvidia and AMD options.
 6) When asked what type of system you want, the correct choice is "desktop" and the correct desktop environment is "Gnome".
 7) For sound, "pipewire" is strongly recommended for the sound system choice during install. This is known to work really well with Jitsi, Element, and the other Federated Core SaaS applications, if you're using those. This may no longer be required in the newest installations of Arch Linux.
@@ -47,6 +48,8 @@ To list the wireless adapters type: `device list`. If your wireless device is "w
 
 When you have the wireless network working (check by doing "ping google.com"), then you can proceed to install Arch.
 
+This connection is only for the installer: `iwctl` saves your Wi-Fi password on the USB stick, not on your new system. Choose "Use NetworkManager" at archinstall's network step, and after the first boot choose your Wi-Fi network in GNOME's top-right menu.
+
 ## Installing Federated CoreDesktop
 
 When Arch and Gnome have been successfully installed, you log in to the system then...
@@ -177,6 +180,7 @@ Besides installing software, CoreDesktop changes these settings. They're listed
 - **systemd**: a 10-second stop timeout (/etc/systemd/system.conf.d/ and /etc/systemd/user.conf.d/10-coredesktop-timeout.conf), systemd-oomd for apps (/etc/systemd/user/app.slice.d/10-coredesktop-oomd.conf), and NetworkManager-wait-online is masked.
 - **/etc/security/pam_env.conf**: a PATH line, so SSH commands find ~/.local/bin and mise.
 - **mDNS**: Avahi is on, nss-mdns is added to /etc/nsswitch.conf, and SSH is advertised in /etc/avahi/services/ssh.service.
+- **Wi-Fi**: if iwd is turned on alongside NetworkManager (archinstall's "Copy ISO network configuration" does that), iwd and systemd-networkd are turned off, so that NetworkManager runs the network from the next restart. Choose your Wi-Fi network once in GNOME's top-right menu after that restart. If you set NetworkManager to use iwd itself (`wifi.backend=iwd`), this leaves iwd alone.
 - **Services turned on**: Avahi, Bluetooth, CUPS (printing), fwupd, GDM, NetworkManager, reflector (weekly), sshd, Docker, Tailscale, ufw and systemd-oomd. Your user is added to the docker group.
 - **Snapper** (btrfs only): a config for / in /etc/snapper/configs/root.
 - **NVIDIA** (only if it installs the driver): /etc/mkinitcpio.conf.d/nvidia.conf and NVIDIA's suspend services.