A tenant's administrator can turn legacy mail apps off for the organization

INBUXA's tenant switch (legacy-protocols LP-9 to LP-18) in the
administration. Each tenant's sheet gains "Legacy mail apps": whether IMAP,
POP3, ManageSieve and sending from mail apps are on or off on the tenant's
domains, and the switch.

Nobody turns it off by accident. "Turn off legacy protocols…" first shows
who would notice -- every account in the tenant that signed in with a
legacy mail app in the last 30 days, with the protocols and when (LP-15) --
and the statement of what it means, "for everyone in {tenant}" (LP-16),
then asks for the phrase "turn off legacy mail", matched exactly (LP-17).
Turning it back on is one click; the server refuses while it has legacy
protocols off for everyone, and its words are shown. A tenant's switch
closes no port, so the statement names none.

It needs the domain permissions the server checks for the switch; with
read-only access the state shows and the buttons don't. On a server that
isn't INBUXA, or is older, the section isn't there.

The dashboard says so while legacy mail is off for the signed-in
administrator's organization (LP-18), from the same session flag as
Settings › Security's line.

Every new string in all nine languages, the register each catalog uses, and
the count in each language's plural forms.

web/src/views/admin/AdminDashboard.tsx

@@ -1,6 +1,8 @@
 import { useEffect, useState, type ReactNode } from "react";
 import { Link } from "wouter";
-import { ArrowDownToLine, ArrowUpFromLine, ExternalLink, Globe, Hourglass, LayoutDashboard, MemoryStick, RefreshCw, Users } from "lucide-react";
+import { ArrowDownToLine, ArrowUpFromLine, ExternalLink, Globe, Hourglass, LayoutDashboard, MemoryStick, RefreshCw, ShieldCheck, Users } from "lucide-react";
+import { legacyProtocolsOff } from "@/jmap/client";
+import { useAppName } from "@/lib/brand";
 import { adminSections, dashboardCards, type DashboardCard } from "@/lib/admin/adminAccess";
 import { balancedColumns, countObjects, DASHBOARD_WINDOW_MS, isRefused, loadMetrics, summarizeMetrics, type MessageStats } from "@/lib/admin/adminDashboard";
 import { formatDayMonthTime, resolvedLocale } from "@/lib/datetime";
@@ -35,6 +37,8 @@ async function settle<T>(work: Promise<T>): Promise<Loaded<T>> {
 export function AdminDashboard() {
   const perms = usePermissions();
   const adminUrl = useSession((s) => s.session?.ihasmail?.server?.adminUrl ?? null);
+  const legacyOff = useSession((s) => legacyProtocolsOff(s.session, s.accountId));
+  const app = useAppName();
   const cards = dashboardCards(perms);
   const sections = adminSections(perms);
   const [reload, setReload] = useState(0);
@@ -102,6 +106,13 @@ export function AdminDashboard() {
           <RefreshCw size={18} />
         </button>
       </div>
+      {legacyOff && (
+        // INBUXA legacy-protocols LP-18: while it's off for the organization
+        <p className="admin-notice">
+          <ShieldCheck size={16} />
+          <span>{t("Legacy mail protocols are off for your organization. Only {app} and JMAP apps can sign in.", { app })}</span>
+        </p>
+      )}
       {shown.length ? (
         <div className="admin-cards-wrap">
           <div className="admin-cards">