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/unit/marquee-settings.test.ts

@@ -0,0 +1,85 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  buildDefaultMarqueeSettings,
+  parseMarqueeSettingsValue,
+  splitMarqueeRowItems,
+  syncMarqueeSettingsToGermanSource,
+} from "@/lib/marquee-settings";
+
+describe("buildDefaultMarqueeSettings", () => {
+  it("provides all four rows for every locale", () => {
+    const settings = buildDefaultMarqueeSettings();
+    for (const locale of ["ar", "en", "de"] as const) {
+      expect(settings.locales[locale].row1).toContain("Next.js");
+      expect(settings.locales[locale].row2).toContain("TypeScript");
+      expect(settings.locales[locale].row3).toContain("JavaScript");
+      expect(settings.locales[locale].row4).toContain("Frontend Strategy");
+    }
+  });
+});
+
+describe("syncMarqueeSettingsToGermanSource", () => {
+  it("copies the german rows over english and arabic", () => {
+    const base = buildDefaultMarqueeSettings();
+    base.locales.de.row1 = "GERMAN";
+    base.locales.en.row1 = "english";
+    base.locales.ar.row1 = "arabic";
+    const synced = syncMarqueeSettingsToGermanSource(base);
+    expect(synced.locales.de.row1).toBe("GERMAN");
+    expect(synced.locales.en.row1).toBe("GERMAN");
+    expect(synced.locales.ar.row1).toBe("GERMAN");
+  });
+
+  it("returns independent copies (no shared references)", () => {
+    const synced = syncMarqueeSettingsToGermanSource(buildDefaultMarqueeSettings());
+    synced.locales.en.row1 = "changed";
+    expect(synced.locales.de.row1).not.toBe("changed");
+  });
+});
+
+describe("parseMarqueeSettingsValue", () => {
+  it("returns german-synced defaults for empty input", () => {
+    const settings = parseMarqueeSettingsValue(null);
+    expect(settings.locales.en.row1).toBe(settings.locales.de.row1);
+    expect(settings.locales.de.row1).toContain("Next.js");
+  });
+
+  it("returns defaults for invalid json", () => {
+    const settings = parseMarqueeSettingsValue("{not json");
+    expect(settings.locales.de.row1).toContain("Next.js");
+  });
+
+  it("normalizes stored values, trims, and syncs to german", () => {
+    const settings = parseMarqueeSettingsValue(
+      JSON.stringify({
+        locales: {
+          de: { row1: "  Custom Row 1  ", row2: "R2", row3: "R3", row4: "R4" },
+          en: { row1: "IGNORED" },
+        },
+      }),
+    );
+    expect(settings.locales.de.row1).toBe("Custom Row 1");
+    // english is overwritten by the german source
+    expect(settings.locales.en.row1).toBe("Custom Row 1");
+    expect(settings.locales.ar.row2).toBe("R2");
+  });
+
+  it("falls back to per-row defaults when a row is blank", () => {
+    const settings = parseMarqueeSettingsValue(
+      JSON.stringify({ locales: { de: { row1: "   ", row2: "", row3: "R3", row4: "R4" } } }),
+    );
+    expect(settings.locales.de.row1).toContain("Next.js");
+    expect(settings.locales.de.row3).toBe("R3");
+  });
+});
+
+describe("splitMarqueeRowItems", () => {
+  it("splits on newlines and commas and trims blanks", () => {
+    expect(splitMarqueeRowItems("A\nB, C\n\n , D")).toEqual(["A", "B", "C", "D"]);
+  });
+
+  it("returns an empty array for whitespace-only input", () => {
+    expect(splitMarqueeRowItems("   \n  ")).toEqual([]);
+  });
+});