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/api/v1/admin/webhooks/route.ts

@@ -0,0 +1,65 @@
+import { NextRequest, NextResponse } from "next/server";
+import crypto from "node:crypto";
+import { z } from "zod";
+import { db, adminWebhooks } from "@epicure/db";
+import { requireAdmin } from "@/lib/api-auth";
+import { validateWebhookUrl } from "@/lib/validate-webhook-url";
+import { ADMIN_WEBHOOK_EVENTS } from "@/lib/admin-webhooks";
+import { encrypt } from "@/lib/encrypt";
+
+const CreateWebhookBody = z.object({
+  url: z.string().min(1).max(2048),
+  events: z.array(z.enum(ADMIN_WEBHOOK_EVENTS)).default([]),
+});
+
+export async function GET() {
+  const { response } = await requireAdmin();
+  if (response) return response;
+
+  const rows = await db
+    .select({
+      id: adminWebhooks.id,
+      url: adminWebhooks.url,
+      events: adminWebhooks.events,
+      active: adminWebhooks.active,
+      createdAt: adminWebhooks.createdAt,
+    })
+    .from(adminWebhooks);
+
+  return NextResponse.json(rows);
+}
+
+export async function POST(req: NextRequest) {
+  const { session, response } = await requireAdmin();
+  if (response) return response;
+
+  const body = await req.json() as unknown;
+  const parsed = CreateWebhookBody.safeParse(body);
+  if (!parsed.success) {
+    return NextResponse.json({ error: "Validation error", issues: parsed.error.issues }, { status: 400 });
+  }
+
+  const ssrfError = await validateWebhookUrl(parsed.data.url);
+  if (ssrfError) {
+    return NextResponse.json({ error: ssrfError }, { status: 400 });
+  }
+
+  const secret = crypto.randomBytes(32).toString("hex");
+  const id = crypto.randomUUID();
+  const now = new Date();
+
+  await db.insert(adminWebhooks).values({
+    id,
+    createdById: session!.user.id,
+    url: parsed.data.url,
+    events: parsed.data.events,
+    secret: encrypt(secret),
+    active: true,
+    createdAt: now,
+  });
+
+  return NextResponse.json(
+    { id, url: parsed.data.url, events: parsed.data.events, secret, active: true, createdAt: now.toISOString() },
+    { status: 201 }
+  );
+}