test(integration): add real-stack integration test suite with PGlite

- PGlite (in-memory WASM Postgres) hosted in a child process, exposed
  via TCP socket; real migrations applied with prisma migrate deploy
- Vitest harness (vitest.integration.config.ts, global-setup spawns
  PGlite + built Nuxt server, per-test TRUNCATE, factories, cookie-jar
  API client); no mocks, zero production code changes
- 50 tests across auth, hunt, team, submit, review, showcase, diashow
  incl. SuperJSON envelope check; *.itest.ts keeps bun test untouched
- CI: parallel unit + integration jobs in .github/workflows/test.yml
- tests/ covered by nuxt typecheck via tests/tsconfig.json reference

tests/integration/setup.ts

@@ -0,0 +1,11 @@
+import { inject } from 'vitest';
+
+export const baseUrl = inject('baseUrl');
+
+// Must be set before the first import of ~~/lib/prisma, which reads
+// DATABASE_URL at import time.
+process.env.DATABASE_URL = inject('databaseUrl');
+
+const { default: prisma } = await import('~~/lib/prisma');
+
+export { prisma };