Add administrative room close and reopen controls

Preserve readable private tables, discussion and pending games while closure blocks new play, joins, messages, AI and seat mutations. Add live-authorized atomic closure audits, room-version/revision fences, dedicated controls and exact saved retries. Reopen with the saved pause/join settings and current credentials; restoring a removed but closed room keeps its AI stopped.

Verified types, lint, 5356 offline tests, 52 HTTP tests and build. Seventeen dedicated authenticated HTTP groups and independent privacy/persistence review passed. Desktop/mobile browser QA confirmed one close after a lost response and refresh, persistent readable notices, retained private draft, mobile reopening and saved-seat refresh. All 2,001 baseline rooms, 4,243 seats and related records preserved. Positive production admin acceptance awaits authorized QA access; full admin and rules gates remain open.

lib/admin-closure.ts

@@ -0,0 +1,63 @@
+export type AdminClosureInput = {
+  operationId: string;
+  expectedVersion: number;
+  expectedRevision: number;
+  closed: boolean;
+  reason: string;
+};
+
+export type AdminClosureView = {
+  removed: boolean;
+  code: string;
+  version: number;
+  closed: boolean;
+  revision: number;
+  closedAt: number | null;
+  updatedAt: number | null;
+  paused: boolean;
+  joinLocked: boolean;
+};
+
+export type AdminClosureResult = {
+  operationId: string;
+  replayed: boolean;
+  appliedRevision: number;
+  appliedVersion: number;
+  room: AdminClosureView;
+};
+
+export function validAdminClosureInput(
+  value: unknown,
+): value is AdminClosureInput {
+  if (!value || typeof value !== 'object' || Array.isArray(value)) return false;
+  const input = value as Record<string, unknown>;
+  const fields = [
+    'operationId',
+    'expectedVersion',
+    'expectedRevision',
+    'closed',
+    'reason',
+  ];
+  return (
+    Object.keys(input).length === fields.length &&
+    fields.every((field) => Object.hasOwn(input, field)) &&
+    typeof input.operationId === 'string' &&
+    input.operationId.length === 36 &&
+    /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/.test(
+      input.operationId,
+    ) &&
+    [input.expectedVersion, input.expectedRevision].every(
+      (version) =>
+        Number.isSafeInteger(version) &&
+        Number(version) >= 0 &&
+        Number(version) < Number.MAX_SAFE_INTEGER,
+    ) &&
+    typeof input.closed === 'boolean' &&
+    typeof input.reason === 'string' &&
+    !!input.reason.trim() &&
+    input.reason.length <= 300 &&
+    !input.reason
+      .split('')
+      .some((char) => char.charCodeAt(0) < 32 || char.charCodeAt(0) === 127)
+  );
+}