feat(og): capa do projeto como fundo da imagem de compartilhamento dos cases

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>

lib/og-card.test.tsx

@@ -0,0 +1,36 @@
+import { render } from "@testing-library/react";
+import { OgCard, readProjectOgBackground } from "./og-card";
+
+describe("readProjectOgBackground", () => {
+  it("returns the recorded cover of a showcase project as a JPEG data URI", () => {
+    const uri = readProjectOgBackground("nutriscan");
+    expect(uri).toMatch(/^data:image\/jpeg;base64,/);
+    expect((uri ?? "").length).toBeGreaterThan(5_000);
+  });
+
+  it("returns undefined for projects without a recorded cover", () => {
+    expect(readProjectOgBackground("twins-lab")).toBeUndefined();
+    expect(readProjectOgBackground("../../etc/passwd")).toBeUndefined();
+  });
+});
+
+describe("OgCard", () => {
+  const props = { eyebrow: "Case", title: "Título", description: "Resumo." };
+
+  it("keeps the plain dark card when there is no background", () => {
+    const { container } = render(<OgCard {...props} />);
+    // só a marca
+    expect(container.querySelectorAll("img")).toHaveLength(1);
+  });
+
+  it("puts the project cover behind the text with a darkening gradient", () => {
+    const { container } = render(
+      <OgCard {...props} backgroundImage="data:image/jpeg;base64,AAAA" />,
+    );
+    const images = [...container.querySelectorAll("img")];
+    expect(images).toHaveLength(2);
+    expect(images[0]).toHaveAttribute("src", "data:image/jpeg;base64,AAAA");
+    expect(images[0]).toHaveAttribute("alt", "");
+    expect(container.innerHTML).toContain("linear-gradient");
+  });
+});