fix: remove dead imports from StatsTab after PR #212 merge

RecentErrorGroup, formatDistanceToNow, and XCircle were left over from
the old inline error list replaced by <RecentErrorsCard />.

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

Author: tombii

packages/dashboard-web/src/components/StatsTab.tsx

@@ -1,7 +1,5 @@
-import type { RecentErrorGroup } from "@better-ccflare/types";
 import { formatPercentage } from "@better-ccflare/ui-common";
-import { formatDistanceToNow } from "date-fns";
-import { RefreshCw, XCircle } from "lucide-react";
+import { RefreshCw } from "lucide-react";
 import { useResetStats, useStats } from "../hooks/queries";
 import { useApiError } from "../hooks/useApiError";
 import { RecentErrorsCard } from "./overview/system-status/RecentErrorsCard";