Add WireGuard, DNS and more to the web UI and router-setup

Web UI: a WireGuard page (tunnels, peers, keys made on the router, client
configs with a QR code, import of wg-quick configs, live status), a DNS page
(records, wildcards, forward zones), interface dropdowns with VLAN devices,
IPv6 options and a local domain. router-setup asks about VLANs, IPv6 and
the domain. The router publishes its own name in DNS and hands the local
domain to DHCP clients; wg and jq are on the router. Includes a script
that takes over antigua's tunnels.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AeFqV9dZrK6nipHkPfyM4F

modules/installer/setup.nix

@@ -113,7 +113,7 @@ let
       }
 
       # Set by ask/choose (printf -v).
-      disk="" wan="" lan="" wan_type="" want_vlans="" want_v6="" vlan_parent="" vlan_id="" host="" lan_address="" ssh_key="" answer=""
+      disk="" domain="" wan="" lan="" wan_type="" want_vlans="" want_v6="" vlan_parent="" vlan_id="" host="" lan_address="" ssh_key="" answer=""
       webui_password="" webui_password2="" reuse="" reuse_label="" new=""
 
       work=$(mktemp -d /run/router-setup.XXXXXX)
@@ -326,6 +326,12 @@ let
         yes_no want_v6 "Enable IPv6 (the provider delegates a prefix to the LAN)?" y
         echo
         ask host "Host name" "router"
+        while :; do
+          ask domain "Local domain for DNS and DHCP, like home.example.org (optional)" ""
+          [ -z "$domain" ] && break
+          [[ $domain =~ ^([a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?\.)*[a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?$ ]] && break
+          echo "  lower case letters, digits, dashes and dots" >&2
+        done
         while :; do
           ask lan_address "Router address on the LAN (a /24 network)" "192.168.1.1"
           ipv4_ok "$lan_address" && break
@@ -348,7 +354,7 @@ let
         echo "  disk:      $disk (will be erased)"
         echo "  WAN:       $wan, $wan_type''${pppoe_user:+ as $pppoe_user}, IPv6 $([ "$want_v6" = y ] && echo on || echo off)"
         echo "  LAN:       $lan, $lan_address/24, DHCP $net.100 - $net.200"
-        echo "  host name: $host"
+        echo "  host name: $host''${domain:+ (domain $domain)}"
         echo "  web UI:    https://$lan_address"
         ask answer "Type the disk name ($disk) to install"
         [ "$answer" = "$disk" ] || { echo "aborted" >&2; exit 1; }
@@ -362,7 +368,7 @@ let
 
         keys=$( [ -n "$ssh_key" ] && jq -n --arg k "$ssh_key" '[$k]' || echo '[]')
         jq -n \
-          --arg host "$host" --arg state "${cfg.stateVersion}" --argjson keys "$keys" \
+          --arg host "$host" --arg domain "$domain" --arg state "${cfg.stateVersion}" --argjson keys "$keys" \
           --argjson schema ${toString cfg.schemaVersion} \
           --arg wan "$wan_dev" --arg type "$wan_type" --arg user "$pppoe_user" --arg vlan "$wan_vlan" \
           --arg lan "$lan_dev" --arg lanvlan "$lan_vlan" --arg v6 "$want_v6" \
@@ -370,7 +376,7 @@ let
           {
             version: $schema,
             system: { hostName: $host, stateVersion: $state, sshKeys: $keys },
-            router: {
+            router: ({
               wan: ({ interface: $wan, ipv4: { type: $type } }
                 | if $type == "pppoe" then .ipv4.pppoe = ({ username: $user, passwordFile: "/var/lib/router/pppoe-password" }
                     + (if $vlan == "" then {} else { vlan: ($vlan | tonumber) } end)) else . end
@@ -385,6 +391,7 @@ let
                 + (if $v6 == "y" then { ipv6: { pd: true } } else {} end))
               }
             }
+            + (if $domain == "" then {} else { dns: { domain: $domain } } end))
           }' > "$config/settings.json"
 
         if [ "$wan_type" = pppoe ]; then