Add data-driven public pages (home, news, profile)

Real App Router pages reading the converted Prisma models:
- home: latest 4 articles (websiteArticles) + hotel_name from settings
- /news + /news/[slug]: article index and detail
- /u/[username]: profile (avatar via imager helper, motto, rank, credits, online)
- shared SiteNav (reads session via auth() + hotel_name), globals.css
- src/lib/format.ts: avatarImageUrl + excerpt helpers (unit-tested)

Verified: tsc exit 0, vitest 43/43, next build exit 0 (7 routes). Pages render
against a live DB (deferred until DATABASE_URL is provided). i18n to be layered
on next.

src/lib/format.test.ts

@@ -0,0 +1,30 @@
+import { describe, expect, it } from "vitest";
+import { avatarImageUrl, excerpt } from "./format";
+
+describe("avatarImageUrl", () => {
+  const base = "https://www.habbo.com/habbo-imaging/avatarimage";
+
+  it("appends the figure and options", () => {
+    const url = avatarImageUrl(base, "hr-100", { size: "l", headOnly: true });
+    expect(url).toContain("figure=hr-100");
+    expect(url).toContain("size=l");
+    expect(url).toContain("headonly=1");
+    expect(url.startsWith(`${base}?`)).toBe(true);
+  });
+
+  it("uses & when the base already has a query string", () => {
+    expect(avatarImageUrl(`${base}?x=1`, "hr-100").includes("?x=1&figure=hr-100")).toBe(true);
+  });
+});
+
+describe("excerpt", () => {
+  it("returns short text unchanged", () => {
+    expect(excerpt("hello", 160)).toBe("hello");
+  });
+
+  it("truncates on a word boundary with an ellipsis", () => {
+    const out = excerpt("the quick brown fox jumps", 12);
+    expect(out).toBe("the quick…");
+    expect(out.length).toBeLessThanOrEqual(13);
+  });
+});