FRE-4471: Scaffold DarkWatch MVP — monorepo, schema, services, API routes, tests

- Turborepo monorepo structure (packages: api, db, types, jobs; services: darkwatch)
- Prisma schema: User, WatchListItem, Exposure, Alert, ScanJob models
- WatchListService: CRUD with normalization, dedup, tier-based limits
- HIBPService: API integration with severity scoring
- MatchingEngine: exact-match with content hash dedup
- AlertPipeline: dedup window, email notifications
- ScanService: orchestrates watch list -> HIBP -> match -> alert flow
- BullMQ job workers for scan and alert processing
- Fastify API routes: watchlist, exposures, alerts, scan
- Docker Compose: PostgreSQL 16 + Redis 7
- 15 unit tests passing
- Implementation plan document uploaded

packages/db/prisma/seed.ts

@@ -0,0 +1,24 @@
+import prisma from "../src";
+
+async function main() {
+  const user = await prisma.user.upsert({
+    where: { email: "dev@shieldai.local" },
+    update: {},
+    create: {
+      email: "dev@shieldai.local",
+      name: "Dev User",
+      subscriptionTier: "PREMIUM",
+    },
+  });
+
+  console.log("Seeded user:", user.email);
+}
+
+main()
+  .catch((e) => {
+    console.error(e);
+    process.exit(1);
+  })
+  .finally(async () => {
+    await prisma.$disconnect();
+  });