Add DNS accounts, Let's Encrypt, password change, reboot, HTTP redirect

- router.dnsProviders: named accounts at DNS providers, used by dynamic
  DNS and certificates (ddclient and lego provider lists in
  pkgs/router-webui/providers.json). Schema 2 migrates router.ddns.
- router.acme: a Let's Encrypt certificate for the web UI via
  security.acme (DNS-01, resolver 1.1.1.1), served and reloaded by the
  web UI; Certificate page.
- Web UI: password change (web UI and root), reboot button, HTTP to HTTPS
  redirect (router.webui.httpPort), grouped menu.
- Latest kernel (linuxPackages_latest); 7.3 and 7.3.0 are the same kernel
  for the reboot hint.
- SPECS.md: wanted later (REST API, GraphQL, MCP).

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

scripts/webui-dev.sh

@@ -8,7 +8,7 @@ mkdir -p "$dir/config"
 wan=$(ip -j route show default 2>/dev/null | jq -r '.[0].dev // empty')
 lan=$(ip -j link show 2>/dev/null | jq -r --arg wan "$wan" '[.[] | select(.link_type == "ether" and .ifname != $wan) | .ifname][0] // "eth1"')
 cat > "$dir/config/settings.json" <<JSON
-{"version": 1, "system": {"hostName": "dev"},
+{"version": 2, "system": {"hostName": "dev"},
  "router": {"wan": {"interface": "${wan:-eth0}", "ipv4": {"type": "dhcp"}},
             "lans": {"lan": {"interface": "$lan", "internet": true, "ipv4": {"address": "192.168.10.1"},
                              "dhcp": {"pool": {"start": "192.168.10.100", "end": "192.168.10.200"}}}}}}
@@ -19,7 +19,7 @@ address,hwaddr,client_id,valid_lifetime,expire,subnet_id,fqdn_fwd,fqdn_rev,hostn
 192.168.10.101,52:54:00:12:34:56,,3600,$((now + 3000)),1,0,0,laptop,0,,0
 192.168.10.120,52:54:00:aa:bb:cc,,3600,$((now + 1200)),1,0,0,phone,0,,0
 LEASES
-echo '{"version": "0.0.0-dev", "serial": 1, "schema": 1}' > "$dir/router-release"
+echo '{"version": "0.0.0-dev", "serial": 1, "schema": 2}' > "$dir/router-release"
 cd "$root/pkgs/router-webui"
 echo devpassword1 | go run . passwd "$dir/webui-password"
 echo