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

vitest.config.ts

@@ -4,14 +4,50 @@ import { fileURLToPath } from "url";
 import { defineConfig } from "vitest/config";
 
 const rootDir = path.dirname(fileURLToPath(new URL(import.meta.url)));
+const alias = { "@": rootDir };
+const esbuild = { jsx: "automatic" as const };
 
 export default defineConfig({
-  resolve: {
-    alias: {
-      "@": rootDir,
-    },
-  },
+  resolve: { alias },
+  esbuild,
   test: {
-    environment: "node",
+    projects: [
+      {
+        resolve: { alias },
+        esbuild,
+        test: {
+          name: "unit",
+          environment: "node",
+          include: ["tests/unit/**/*.test.ts", "tests/*.test.ts"],
+        },
+      },
+      {
+        resolve: { alias },
+        esbuild,
+        test: {
+          name: "integration",
+          environment: "node",
+          include: ["tests/integration/**/*.test.{ts,tsx}"],
+          // One shared test database. Files run sequentially (never in parallel)
+          // but each in its own worker, so every file gets a fresh database
+          // connection and truncation between tests never races another file.
+          fileParallelism: false,
+          globalSetup: ["tests/helpers/global-db-setup.ts"],
+          setupFiles: ["tests/helpers/integration-setup.ts"],
+          hookTimeout: 60_000,
+          testTimeout: 30_000,
+        },
+      },
+      {
+        resolve: { alias },
+        esbuild,
+        test: {
+          name: "component",
+          environment: "jsdom",
+          include: ["tests/component/**/*.test.{ts,tsx}"],
+          setupFiles: ["tests/helpers/component-setup.ts"],
+        },
+      },
+    ],
   },
 });