Add token expiry, edit notice, log allowlist, local-zone test; merge PLAN.md into SPECS.md

get_logs needs a unit from an allowlist (router-*, kea, unbound, networkd,
nftables, ddclient, acme, sshd, kernel). API tokens are valid for 1, 7, 30
(default) or 90 days, or without limit. The overview and the Changes page
say which token made the unapplied changes.

options.json (router://options) no longer holds the options' source paths:
they differ between builds of a release, so a router rebuilding itself
offline had to build the file and failed (found by the update test).

Web UI: panels flow into columns on wide screens and the width is no longer
capped; on phones the navigation is a menu button; the Advanced page uses
panels; VLAN dropdowns show their chosen names; the duplicate WireGuard
heading is gone.

basic: a subtest for wan -> local rules.

SPECS.md is now the only document (decisions, how each part works, and what
is not done yet); PLAN.md is gone.

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

pkgs/router-webui/templates/certificate.html

@@ -1,4 +1,5 @@
 {{define "content"}}
+<div class="cols">
 {{with .Data}}
 {{$e := .Errors}}{{$f := .Form}}
 <section>
@@ -42,4 +43,5 @@
   {{else}}<p class="muted">Nothing yet. After you save and apply, the router orders the certificate (a minute or two); renewals follow 30 days before it expires and need no restart.</p>{{end}}
 </section>
 {{end}}
+</div>
 {{end}}