[taskboard] migrate fleet console to nextjs

app/api/usage/stats/route.ts

@@ -0,0 +1,37 @@
+import { NextResponse } from "next/server";
+
+import { all } from "@/lib/db";
+
+type UsageRow = {
+  agent: string;
+  provider: string;
+  model: string;
+  tokens_used: number;
+  cost_estimate: number;
+};
+
+export async function GET() {
+  const rows = await all<UsageRow>("SELECT * FROM usage_tracking ORDER BY timestamp DESC");
+  const result = rows.reduce(
+    (accumulator, row) => {
+      accumulator.totalRequests += 1;
+      accumulator.totalTokens += row.tokens_used || 0;
+      accumulator.totalCost += row.cost_estimate || 0;
+      if (!accumulator.byAgent[row.agent]) {
+        accumulator.byAgent[row.agent] = { requests: 0, tokens: 0, cost: 0 };
+      }
+      accumulator.byAgent[row.agent].requests += 1;
+      accumulator.byAgent[row.agent].tokens += row.tokens_used || 0;
+      accumulator.byAgent[row.agent].cost += row.cost_estimate || 0;
+      return accumulator;
+    },
+    {
+      totalRequests: 0,
+      totalTokens: 0,
+      totalCost: 0,
+      byAgent: {} as Record<string, { requests: number; tokens: number; cost: number }>,
+    },
+  );
+
+  return NextResponse.json(result);
+}