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/components/settings/settings-sidebar.tsx

@@ -3,7 +3,7 @@
 import Link from "next/link";
 import { usePathname } from "next/navigation";
 import { useTranslations } from "next-intl";
-import { User, Shield, Bot, Bell, Apple, Key, Webhook } from "lucide-react";
+import { User, Shield, Bot, Bell, Apple, Key, Webhook, SlidersHorizontal } from "lucide-react";
 import { cn } from "@/lib/utils";
 
 const NAV_ITEMS = [
@@ -11,6 +11,7 @@ const NAV_ITEMS = [
   { href: "/settings/security", key: "security", icon: Shield, exact: false },
   { href: "/settings/ai", key: "aiModels", icon: Bot, exact: false },
   { href: "/settings/notifications", key: "notifications", icon: Bell, exact: false },
+  { href: "/settings/features", key: "features", icon: SlidersHorizontal, exact: false },
   { href: "/settings/nutrition", key: "nutrition", icon: Apple, exact: false },
   { href: "/settings/api-keys", key: "apiKeys", icon: Key, exact: false },
   { href: "/settings/webhooks", key: "webhooks", icon: Webhook, exact: false },