Add reversible administrator room archiving

Organize closed rooms with archive filters, live-authorized atomic receipts and exact saved retries. Preserve saved games, timestamps, credentials, discussion and AI deadlines. Unarchive leaves play closed; reopen requires unarchive, and removal/restoration preserves both flags.

Verified types, lint, 5379 offline tests, 52 HTTP tests and build. Twenty dedicated administrator HTTP groups and independent privacy/persistence review passed. Desktop/mobile browser QA confirmed a single archive after a lost response and refresh, readable recovery text, mobile unarchive and separate reopening, and saved-seat restoration. All 2,049 baseline rooms, 4,348 seats and related records preserved. Authenticated production admin acceptance awaits authorized QA access; full admin and rules gates remain open.

app/api/admin/rooms/[code]/archive/route.ts

@@ -0,0 +1,33 @@
+import { env } from 'cloudflare:workers';
+import { AdminError, requireAdmin } from '@/db/admin-access';
+import { applyAdminArchive, readAdminArchive } from '@/db/admin-archive';
+import { validAdminArchiveInput } from '@/lib/admin-archive';
+import { adminBody, adminFailure, adminResponse, adminToken } from '@/lib/admin-http';
+
+function code(request: Request) {
+  const code = new URL(request.url).pathname.split('/').at(-2)?.toUpperCase() ?? '';
+  if (code.length !== 8 || !/^[A-Z2-9]{8}$/.test(code)) throw new AdminError('Enter the eight-character room code.', 400);
+  return code;
+}
+
+export async function GET(request: Request) {
+  try {
+    const identity = await requireAdmin(env.DB, adminToken(request));
+    if (request.headers.has('X-Dune-Admin-Id') && request.headers.get('X-Dune-Admin-Id') !== identity.id)
+      throw new AdminError('The signed-in administrator changed. Reload administration before continuing.', 401);
+    return adminResponse(await readAdminArchive(env.DB, identity, code(request)));
+  } catch (error) { return adminFailure(error); }
+}
+
+export async function POST(request: Request) {
+  try {
+    const input = await adminBody(request, env.DUNE_PUBLIC_ORIGIN);
+    const identity = await requireAdmin(env.DB, adminToken(request), ['owner', 'operator']);
+    if (request.headers.get('X-Dune-Admin-Id') !== identity.id)
+      throw new AdminError('The signed-in administrator changed. Reload administration before continuing.', 401);
+    if (!validAdminArchiveInput(input)) throw new AdminError('Choose archive or unarchive, current versions and an operational reason.', 400);
+    const room = code(request);
+    const result = await applyAdminArchive(env.DB, identity, room, input);
+    return adminResponse(result);
+  } catch (error) { return adminFailure(error); }
+}