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/app/u/[username]/page.tsx

@@ -0,0 +1,52 @@
+import { notFound } from "next/navigation";
+import { avatarImageUrl } from "@/lib/format";
+import { prisma } from "@/lib/prisma";
+import { siteSettings } from "@/lib/services/site-settings";
+
+export const dynamic = "force-dynamic";
+
+export default async function ProfilePage({
+  params,
+}: {
+  params: Promise<{ username: string }>;
+}) {
+  const { username } = await params;
+
+  const [user, imagerBase] = await Promise.all([
+    prisma.user.findUnique({
+      where: { username },
+      select: {
+        username: true,
+        motto: true,
+        look: true,
+        rank: true,
+        credits: true,
+        online: true,
+        accountCreated: true,
+      },
+    }),
+    siteSettings.get("habbo_imaging_url", "https://www.habbo.com/habbo-imaging/avatarimage"),
+  ]);
+
+  if (!user) notFound();
+
+  const avatar = avatarImageUrl(imagerBase ?? "", user.look, { size: "l" });
+  const registered = new Date(user.accountCreated * 1000).toISOString().slice(0, 10);
+
+  return (
+    <main>
+      <div className="card" style={{ display: "flex", gap: "1.5rem", alignItems: "center" }}>
+        {/* eslint-disable-next-line @next/next/no-img-element */}
+        <img src={avatar} alt={`${user.username} avatar`} width={100} height={150} />
+        <div>
+          <h1 style={{ margin: "0 0 0.25rem" }}>{user.username}</h1>
+          <p style={{ margin: "0 0 0.5rem" }}>{user.motto || <span className="muted">No motto</span>}</p>
+          <p className="muted" style={{ margin: 0 }}>
+            Rank {user.rank} · {user.credits} credits · {user.online === "1" ? "Online" : "Offline"} ·
+            Registered {registered}
+          </p>
+        </div>
+      </div>
+    </main>
+  );
+}