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/lib/api-auth.ts

@@ -19,7 +19,7 @@ export async function getOptionalSession() {
   return auth.api.getSession({ headers: await headers() });
 }
 
-export async function requireAdmin() {
+export async function requireAdmin(opts?: { allowModerator?: boolean }) {
   const { session, response } = await requireSession();
   if (response) return { session: null, response };
 
@@ -32,7 +32,8 @@ export async function requireAdmin() {
     .where(eq(users.id, session!.user.id))
     .limit(1);
 
-  if (dbUser?.role !== "admin") {
+  const allowed = dbUser?.role === "admin" || (opts?.allowModerator && dbUser?.role === "moderator");
+  if (!allowed) {
     return { session: null, response: NextResponse.json({ error: "Forbidden" }, { status: 403 }) };
   }
   return { session, response: null };