test: add comprehensive automated test coverage

- Vitest multi-project setup (unit / integration / component)
- Real-Postgres integration harness via in-process PGlite (TEST_DATABASE_URL
  override), migrations applied per worker; production code untouched
- Unit: routing, locale, validation/Zod schemas, metadata, mail, site-theme,
  marquee, media, portfolio helpers, plus architecture-rule tests
- Integration: Prisma data layer, API routes, and all server actions
- Component: UI primitives and form components (jsdom + Testing Library)
- 371 tests passing

tests/helpers/global-db-setup.ts

@@ -0,0 +1,35 @@
+import { readFileSync, readdirSync } from "fs";
+import path from "path";
+
+/**
+ * Global integration setup.
+ *
+ * Only needed when running against a real Postgres via TEST_DATABASE_URL: reset the
+ * schema and apply every migration once before the workers start. When
+ * TEST_DATABASE_URL is not set, each worker spins up its own in-process PGlite database
+ * (see tests/helpers/integration-setup.ts) and this is a no-op.
+ */
+
+const MIGRATIONS_DIR = path.resolve(process.cwd(), "prisma", "migrations");
+
+export default async function setup() {
+  const connectionString = process.env.TEST_DATABASE_URL?.trim();
+  if (!connectionString) {
+    return;
+  }
+
+  const pg = (await import("pg")).default;
+  const client = new pg.Client({ connectionString });
+  await client.connect();
+  try {
+    await client.query("DROP SCHEMA IF EXISTS public CASCADE; CREATE SCHEMA public;");
+    const dirs = readdirSync(MIGRATIONS_DIR)
+      .filter((entry) => /^\d/.test(entry))
+      .sort();
+    for (const dir of dirs) {
+      await client.query(readFileSync(path.join(MIGRATIONS_DIR, dir, "migration.sql"), "utf8"));
+    }
+  } finally {
+    await client.end();
+  }
+}