Adapt + improve all public pages to the atom design system

Extended the same design-system treatment to the public site, faithful
to AtomCMS's "atom" theme. New src/components/public/ui.tsx provides the
signature atom building blocks + a scoped CSS layer:
- ContentCard: surface card with a primary-tinted header (icon circle +
  title + subtitle) and padded body — the atom content-card, used as
  every page's header and section wrapper.
- StatBlock / stat-grid, EmptyState, OnlineBadge (online/offline pill),
  RankBadge (medals for the top 3), and responsive .card-grid helpers.

Swept ~45 public pages (home/community/rankings hand-built as the
reference; the rest via parallel agents that read the schema and
preserved every query, server action, auth gate and field name):
heroes → ContentCard headers, lists → card-grids in ContentCards,
"no X" → EmptyState, status → OnlineBadge/RankBadge. The leaderboard
gained Credits/Diamonds/Duckets tabs (usersCurrency).

Behaviour unchanged. Verified on the prod server against amx_test: 15+
public pages render the content-cards/grids with real data, no errors;
computed styles confirm the tinted header, icon circle, medal + online
pills. Fixed an undefined --color-golden ref. tsc 0, vitest 49/49,
next build 0.

src/app/guilds/[id]/forum/new/page.tsx

@@ -1,5 +1,6 @@
 import Link from "next/link";
 import { notFound, redirect } from "next/navigation";
+import { ContentCard } from "@/components/public/ui";
 import { auth } from "@/lib/auth";
 import { prisma } from "@/lib/prisma";
 import { postThread } from "@/actions/social";
@@ -33,54 +34,55 @@ export default async function NewThreadPage({
   if (!guild) notFound();
 
   return (
-    <main>
-      <p style={{ marginTop: 0 }}>
+    <main style={{ display: "grid", gap: "1.5rem" }}>
+      <p style={{ margin: 0 }}>
         <Link href={`/guilds/${guild.id}/forum`}>← Back to forum</Link>
       </p>
 
-      <h1 style={{ marginBottom: "0.25rem" }}>New thread</h1>
-      <p className="muted" style={{ marginTop: 0 }}>
-        in {guild.name || "Unnamed guild"} forum
-      </p>
+      <ContentCard
+        icon="✍️"
+        title="New thread"
+        subtitle={`in ${guild.name || "Unnamed guild"} forum`}
+      >
+        <form action={postThread}>
+          {/* Guild target drives the write; the author is taken from the session
+              inside the action, never from this form. */}
+          <input type="hidden" name="guildId" value={String(guild.id)} />
 
-      <form action={postThread} className="card" style={{ marginTop: "1rem" }}>
-        {/* Guild target drives the write; the author is taken from the session
-            inside the action, never from this form. */}
-        <input type="hidden" name="guildId" value={String(guild.id)} />
+          <label htmlFor="thread-subject" className="muted">
+            Subject
+          </label>
+          <input
+            id="thread-subject"
+            name="subject"
+            required
+            maxLength={255}
+            placeholder="Thread subject"
+            style={{ width: "100%", margin: "0.4rem 0 0.9rem" }}
+          />
 
-        <label htmlFor="thread-subject" className="muted">
-          Subject
-        </label>
-        <input
-          id="thread-subject"
-          name="subject"
-          required
-          maxLength={255}
-          placeholder="Thread subject"
-          style={{ width: "100%", margin: "0.4rem 0 0.9rem" }}
-        />
+          <label htmlFor="thread-message" className="muted">
+            Message
+          </label>
+          <textarea
+            id="thread-message"
+            name="message"
+            required
+            rows={8}
+            placeholder="Write your opening post…"
+            style={{ width: "100%", margin: "0.4rem 0 1rem", resize: "vertical" }}
+          />
 
-        <label htmlFor="thread-message" className="muted">
-          Message
-        </label>
-        <textarea
-          id="thread-message"
-          name="message"
-          required
-          rows={8}
-          placeholder="Write your opening post…"
-          style={{ width: "100%", margin: "0.4rem 0 1rem", resize: "vertical" }}
-        />
-
-        <div style={{ display: "flex", gap: "0.5rem", alignItems: "center" }}>
-          <button type="submit" className="btn btn-primary">
-            Post thread
-          </button>
-          <Link href={`/guilds/${guild.id}/forum`} className="btn btn-outline">
-            Cancel
-          </Link>
-        </div>
-      </form>
+          <div style={{ display: "flex", gap: "0.5rem", alignItems: "center" }}>
+            <button type="submit" className="btn btn-primary">
+              Post thread
+            </button>
+            <Link href={`/guilds/${guild.id}/forum`} className="btn btn-outline">
+              Cancel
+            </Link>
+          </div>
+        </form>
+      </ContentCard>
     </main>
   );
 }