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/mcp.go

@@ -246,6 +246,13 @@ func (a *app) runTool(tok Token, tool *mcpTool, args json.RawMessage) (any, erro
 		entry.Error = err.Error()
 	}
 	a.sys.audit(entry)
+	if err == nil && tool.name == "update_settings" {
+		if m, ok := res.(map[string]any); ok {
+			if e, ok := m["etag"].(string); ok {
+				a.sys.noteTokenEdit(tok.Name, e)
+			}
+		}
+	}
 	return res, err
 }