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.

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

@@ -29,7 +29,7 @@ export async function POST(request: Request) {
     if (!validAdminRemovalInput(input)) throw new AdminError('Choose removal or restoration, current versions and an operational reason.', 400);
     const room = code(request);
     const result = await applyAdminRemoval(env.DB, identity, room, input);
-    if (!result.replayed && !result.room.removed && !result.room.paused) waitUntil(resumeRoom(room));
+    if (!result.replayed && !result.room.removed && !result.room.paused && !result.room.closed) waitUntil(resumeRoom(room));
     return adminResponse(result);
   } catch (error) { return adminFailure(error); }
 }