feat: per-category email prefs, admin ops webhooks, per-user feature toggles (v0.61.0)

- Notification email preferences: every push category (follow, comment,
  reply, reaction, rating, mention, leftoverExpiring, shoppingList) now has
  an independent email toggle, plus a Weekly Digest toggle. Previously email
  sent unconditionally whenever the recipient had one; now gated the same
  way push already was. The weekly-digest cron route excludes opted-out
  users.

- Admin-only site-wide webhooks (Admin → Webhooks): new signups, support
  tickets, and reports filed can now fire an HMAC-signed HTTP webhook
  (Slack/Discord/ops alerting), independent of the existing per-user
  webhooks (which stay scoped to a user's own recipe/meal-plan/shopping-list
  events). Signing/delivery logic factored into lib/webhook-delivery.ts and
  shared by both dispatchers instead of duplicated.

- Settings → Features: users can hide Nutrition, Pantry, Meal Plan,
  Shopping Lists, Collections, or Messages from their own nav. Purely
  cosmetic — hidden pages stay reachable by direct link, nothing is
  access-restricted.

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

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

@@ -0,0 +1,31 @@
+import type { Metadata } from "next";
+import { db, adminWebhooks } from "@epicure/db";
+import { AdminWebhooksManager } from "@/components/admin/admin-webhooks-manager";
+
+export const metadata: Metadata = {};
+
+export default async function AdminWebhooksPage() {
+  const rows = await db
+    .select({
+      id: adminWebhooks.id,
+      url: adminWebhooks.url,
+      events: adminWebhooks.events,
+      active: adminWebhooks.active,
+      createdAt: adminWebhooks.createdAt,
+    })
+    .from(adminWebhooks);
+
+  const webhooks = rows.map((w) => ({ ...w, createdAt: w.createdAt.toISOString() }));
+
+  return (
+    <div className="space-y-6">
+      <div>
+        <h1 className="text-2xl font-bold tracking-tight">Webhooks</h1>
+        <p className="text-muted-foreground text-sm mt-1">
+          Site-wide ops events (new signups, support tickets, reports) — deliver to any HTTP endpoint (Slack/Discord incoming webhook, internal alerting, etc). Fires regardless of who&apos;s involved, unlike the per-user webhooks under Settings.
+        </p>
+      </div>
+      <AdminWebhooksManager initialWebhooks={webhooks} />
+    </div>
+  );
+}