fix: add rAuctions module stub to fix missing import crash

The server imported rauctions/mod but the module was never committed,
causing a crash loop on startup.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

modules/rauctions/mod.ts

@@ -0,0 +1,20 @@
+/**
+ * rAuctions module — Community auctions with USDC (stub).
+ * TODO: Implement auction logic.
+ */
+
+import { Hono } from 'hono';
+import type { RSpaceModule } from '../../shared/module';
+
+const routes = new Hono();
+
+routes.get('/', (c) => c.text('rAuctions — coming soon'));
+
+export const auctionsModule: RSpaceModule = {
+	id: 'auctions',
+	name: 'rAuctions',
+	icon: '🏛',
+	description: 'Community auctions with USDC',
+	routes,
+	scoping: { scope: 'space', default: 'disabled' },
+};