Add register + logout auth flows, and batch-5 resources

Auth (hand-built, uses the auth core):
- /register + register() action: validates, hashes with argon2id (hashPassword),
  creates an emulator-compatible users row (accountCreated/ipRegister/ipCurrent/
  look), redirect kept outside try so NEXT_REDIRECT propagates. Login/register
  cross-links; header shows Register (logged-out) and a Logout (signOut) button.

Batch 5 (parallel agents): /admin/rooms (+[id]) search+detail, /admin/vouchers
(CRUD), /admin/subscriptions (read), /admin/calendar (campaigns+rewards read),
/marketplace (public). Header + admin nav extended.

Verified: tsc exit 0, vitest 48/48, next build exit 0 (52 page routes).

src/app/admin/calendar/page.tsx

@@ -0,0 +1,99 @@
+import Link from "next/link";
+import { prisma } from "@/lib/prisma";
+
+export const dynamic = "force-dynamic";
+
+type Campaign = {
+  id: number;
+  name: string;
+  image: string;
+  startTimestamp: number;
+  totalDays: number;
+  lockExpired: string;
+  enabled: string;
+};
+
+function fmtDate(ts: number): string {
+  if (!ts) return "—";
+  return new Date(ts * 1000).toISOString().slice(0, 10);
+}
+
+export default async function AdminCalendar() {
+  let campaigns: Campaign[] = [];
+  try {
+    campaigns = await prisma.calendarCampaigns.findMany({
+      select: {
+        id: true,
+        name: true,
+        image: true,
+        startTimestamp: true,
+        totalDays: true,
+        lockExpired: true,
+        enabled: true,
+      },
+      orderBy: { id: "desc" },
+    });
+  } catch {
+    campaigns = [];
+  }
+
+  // Tally reward counts per campaign in JS (avoid prisma.groupBy).
+  const rewardCounts = new Map<number, number>();
+  try {
+    const rewards = await prisma.calendarRewards.findMany({
+      select: { campaignId: true },
+    });
+    for (const r of rewards) {
+      rewardCounts.set(r.campaignId, (rewardCounts.get(r.campaignId) ?? 0) + 1);
+    }
+  } catch {
+    // leave map empty on failure
+  }
+
+  return (
+    <main>
+      <h1>Calendar campaigns</h1>
+      <p className="muted" style={{ marginTop: 0 }}>
+        Read-only · {campaigns.length} campaign{campaigns.length === 1 ? "" : "s"}.
+      </p>
+
+      {campaigns.length === 0 ? (
+        <p className="muted">No calendar campaigns found.</p>
+      ) : (
+        <div className="grid cols-3">
+          {campaigns.map((c) => {
+            const disabled = c.enabled !== "1";
+            const count = rewardCounts.get(c.id) ?? 0;
+            return (
+              <Link
+                key={c.id}
+                href={`/admin/calendar/${c.id}`}
+                className="card hover article"
+                style={{ color: "inherit" }}
+              >
+                {c.image ? (
+                  // eslint-disable-next-line @next/next/no-img-element
+                  <img className="article-img" src={c.image} alt={c.name} />
+                ) : (
+                  <div className="article-img" />
+                )}
+                <div className="body">
+                  <h3 style={{ margin: "0 0 0.35rem" }}>{c.name || `Campaign #${c.id}`}</h3>
+                  <p className="muted" style={{ margin: 0 }}>
+                    #{c.id} · {c.totalDays} day{c.totalDays === 1 ? "" : "s"} · {count} reward
+                    {count === 1 ? "" : "s"}
+                  </p>
+                  <p className="muted" style={{ margin: "0.35rem 0 0" }}>
+                    Starts {fmtDate(c.startTimestamp)}
+                    {disabled ? " · Disabled" : ""}
+                    {c.lockExpired === "1" ? " · Locks expired" : ""}
+                  </p>
+                </div>
+              </Link>
+            );
+          })}
+        </div>
+      )}
+    </main>
+  );
+}