fix: move seed command to prisma.config.ts (Prisma 7 requirement)

Prisma 7 no longer reads the seed command from package.json.
It must be set in prisma.config.ts under migrations.seed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

prisma.config.ts

@@ -7,6 +7,7 @@ export default defineConfig({
   schema: "prisma/schema.prisma",
   migrations: {
     path: "prisma/migrations",
+    seed: "tsx prisma/seed.ts",
   },
   datasource: {
     url: process.env["DATABASE_URL"],