feat(admin): add manual R2 stats refresh endpoint/button and share in-memory storage snapshot cache

app/api/admin/stats/refresh-r2/route.ts

@@ -0,0 +1,22 @@
+import { auth } from '@/lib/auth';
+import { apiErrors, successResponse } from '@/lib/api-response';
+import { refreshR2StorageSnapshot } from '@/lib/admin-stats';
+
+export async function POST() {
+  try {
+    const session = await auth();
+    if (!session?.user?.isAdmin) {
+      return apiErrors.forbidden('Admin access required');
+    }
+
+    const refreshedAt = await refreshR2StorageSnapshot();
+
+    return successResponse({
+      ok: true,
+      refreshedAt,
+    });
+  } catch (error) {
+    console.error('Error refreshing R2 admin stats cache:', error);
+    return apiErrors.internalError('Failed to refresh R2 stats');
+  }
+}