feat: moderator-scoped admin access + fix push notifications not displaying (v0.66.0)

Moderator role existed in the schema and was already respected by
comment deletion, but every admin page/route treated moderator
identically to a regular user (403/redirect). Wires it up narrowly:
admin/layout.tsx now lets admin+moderator through and filters the
nav by role, while every admin-only page (users, tiers, settings,
webhooks, insights, etc.) explicitly redirects moderators away via a
new requireFullAdminPage() helper -- the nav filter is UX, this is
the actual gate. Moderators land on Reports and Recipes: reports
GET/PATCH now accept requireAdmin({allowModerator: true}), and a new
PATCH /api/v1/admin/recipes/[id] lets admin+moderator unpublish a
public recipe (flip to private) as a takedown action, audit-logged.

Also found and fixed a real bug while auditing the PWA push pipeline
for a "push click-through" gap: public/sw.js had no `push` event
listener at all, so incoming push messages never displayed anything
-- push was silently non-functional end-to-end despite the
subscribe/send plumbing all working. Added the push listener
(showNotification) and a notificationclick listener that focuses an
existing tab or opens one at the payload's url.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/app/admin/users/page.tsx

@@ -6,6 +6,7 @@ import { Badge } from "@/components/ui/badge";
 import { Avatar, AvatarFallback, AvatarImage } from "@/components/ui/avatar";
 import { CreateUserDialog } from "@/components/admin/create-user-dialog";
 import Link from "next/link";
+import { requireFullAdminPage } from "@/lib/require-admin-page";
 
 export const metadata: Metadata = {};
 
@@ -28,6 +29,7 @@ const TIER_COLORS = {
 } as const;
 
 export default async function AdminUsersPage({ searchParams }: PageProps) {
+  await requireFullAdminPage();
   const { page: pageParam } = await searchParams;
   const page = Math.max(1, parseInt(pageParam ?? "1", 10) || 1);
   const offset = (page - 1) * PAGE_SIZE;