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/component-setup.ts

@@ -0,0 +1,133 @@
+import { cleanup } from "@testing-library/react";
+import { afterEach, vi } from "vitest";
+import "@testing-library/jest-dom/vitest";
+import React from "react";
+
+afterEach(() => {
+  cleanup();
+});
+
+// ---------------------------------------------------------------------------
+// Global mocks for heavy / browser-only libraries so components render in jsdom.
+// (vi.mock in a setup file applies to every test file in the component project.)
+// ---------------------------------------------------------------------------
+
+vi.mock("framer-motion", () => {
+  const passthrough = (tag: string) =>
+    React.forwardRef(function MotionMock(
+      { children, ...props }: Record<string, unknown> & { children?: React.ReactNode },
+      ref: React.Ref<unknown>,
+    ) {
+      const domProps: Record<string, unknown> = {};
+      for (const [key, value] of Object.entries(props)) {
+        // Drop motion-only props that would warn as unknown DOM attributes.
+        if (
+          /^(initial|animate|exit|transition|variants|whileHover|whileTap|whileInView|whileFocus|whileDrag|drag|layout|layoutId|viewport|custom|onAnimationComplete|style)$/.test(
+            key,
+          )
+        ) {
+          if (key === "style") domProps.style = value;
+          continue;
+        }
+        domProps[key] = value;
+      }
+      return React.createElement(tag, { ...domProps, ref }, children as React.ReactNode);
+    });
+
+  const motion = new Proxy(
+    {},
+    {
+      get: (_target, tag: string) => passthrough(tag),
+    },
+  );
+
+  return {
+    motion,
+    AnimatePresence: ({ children }: { children?: React.ReactNode }) =>
+      React.createElement(React.Fragment, null, children),
+    useReducedMotion: () => true,
+    useInView: () => true,
+    useScroll: () => ({ scrollYProgress: { on: () => () => {}, get: () => 0 } }),
+    useTransform: () => 0,
+    useMotionValue: (value: unknown) => ({ get: () => value, set: () => {}, on: () => () => {} }),
+    useAnimate: () => [React.useRef(null), () => Promise.resolve()],
+  };
+});
+
+vi.mock("gsap", () => {
+  const tween = { kill: () => {}, play: () => {}, pause: () => {}, progress: () => {} };
+  const gsap = {
+    to: () => tween,
+    from: () => tween,
+    fromTo: () => tween,
+    set: () => tween,
+    timeline: () => ({
+      to: () => ({}),
+      from: () => ({}),
+      fromTo: () => ({}),
+      add: () => ({}),
+      kill: () => {},
+    }),
+    registerPlugin: () => {},
+    context: (fn: () => void) => {
+      if (typeof fn === "function") fn();
+      return { revert: () => {}, kill: () => {} };
+    },
+    matchMedia: () => ({ add: () => {}, revert: () => {} }),
+    utils: { toArray: (v: unknown) => (Array.isArray(v) ? v : [v]) },
+  };
+  return { gsap, default: gsap };
+});
+
+vi.mock("@gsap/react", () => ({
+  useGSAP: () => ({ context: {}, contextSafe: (fn: unknown) => fn }),
+}));
+
+vi.mock("next/link", () => ({
+  default: React.forwardRef(function LinkMock(
+    { href, children, ...props }: Record<string, unknown> & { href?: unknown; children?: React.ReactNode },
+    ref: React.Ref<HTMLAnchorElement>,
+  ) {
+    return React.createElement("a", { href: String(href ?? ""), ref, ...props }, children as React.ReactNode);
+  }),
+}));
+
+vi.mock("next/image", () => ({
+  default: ({ src, alt, ...props }: Record<string, unknown> & { src?: unknown; alt?: string }) =>
+    React.createElement("img", { src: String(src ?? ""), alt: alt ?? "", ...props }),
+}));
+
+vi.mock("next/navigation", () => ({
+  usePathname: () => "/",
+  useRouter: () => ({
+    push: vi.fn(),
+    replace: vi.fn(),
+    refresh: vi.fn(),
+    back: vi.fn(),
+    forward: vi.fn(),
+    prefetch: vi.fn(),
+  }),
+  useSearchParams: () => new URLSearchParams(),
+  useParams: () => ({}),
+  redirect: vi.fn(),
+  notFound: vi.fn(),
+}));
+
+vi.mock("next-intl", () => ({
+  useTranslations: () => {
+    const t = (key: string) => key;
+    t.rich = (key: string) => key;
+    t.markup = (key: string) => key;
+    t.raw = (key: string) => key;
+    return t;
+  },
+  useLocale: () => "de",
+  useFormatter: () => ({
+    dateTime: (v: Date) => v.toISOString(),
+    number: (v: number) => String(v),
+    relativeTime: (v: unknown) => String(v),
+  }),
+  useMessages: () => ({}),
+  NextIntlClientProvider: ({ children }: { children?: React.ReactNode }) =>
+    React.createElement(React.Fragment, null, children),
+}));