feat: add public avatar thumbnail contract

src/components/shared/user-avatar-thumbnail.test.tsx

@@ -0,0 +1,24 @@
+import { renderToStaticMarkup } from "react-dom/server";
+import { describe, expect, it } from "vitest";
+import { UserAvatarThumbnail } from "./user-avatar-thumbnail";
+
+describe("UserAvatarThumbnail", () => {
+	it("renders the supplied figure as a fixed head-only thumbnail", () => {
+		const html = renderToStaticMarkup(
+			<UserAvatarThumbnail
+				figure="hd-180-1.hr-828-45"
+				alt="Life avatar"
+				options={{ direction: 3 }}
+			/>,
+		);
+
+		expect(html).toContain("figure=hd-180-1.hr-828-45");
+		expect(html).toContain("headonly=1");
+		expect(html).toContain("size=l");
+		expect(html).toContain("direction=3");
+		expect(html).toContain('width="40"');
+		expect(html).toContain('height="40"');
+		expect(html).toContain('alt="Life avatar"');
+		expect(html).toContain("shrink-0");
+	});
+});