feat(ops): usage dashboard UI with charts and tables

- Add hourly/daily time buckets and buildUsageTimeSeriesJson
- Render /ops/usage with Chart.js (CDN): line + doughnut
- Tables: actors by type, by service, search breakdown
- GET /ops/usage/api/timeseries for JSON; collapsible raw payload

Made-with: Cursor

Author: ilyar

src/__tests__/usage-db.test.ts

@@ -2,7 +2,7 @@ import { describe, expect, it, beforeEach, afterEach } from "vitest";
 import { mkdtempSync, rmSync } from "node:fs";
 import { join } from "node:path";
 import { tmpdir } from "node:os";
-import { buildUsageSummaryJson } from "../usage/dashboard.js";
+import { buildUsageSummaryJson, buildUsageTimeSeriesJson } from "../usage/dashboard.js";
 import { recordUsageEvent, resetUsageDbForTests } from "../usage/db.js";
 
 describe("usage SQLite", () => {
@@ -61,4 +61,29 @@ describe("usage SQLite", () => {
     expect(mcp?.c).toBe(1);
     expect(search?.c).toBe(2);
   });
+
+  it("time series sums to total events in window", () => {
+    recordUsageEvent({
+      service: "search",
+      eventType: "search_query",
+      actorType: "anonymous_ip",
+      actorKey: "a",
+      tier: "free",
+    });
+    recordUsageEvent({
+      service: "landing",
+      eventType: "pixel",
+      actorType: "anonymous_ip",
+      actorKey: "b",
+    });
+
+    const series = buildUsageTimeSeriesJson(24) as {
+      enabled?: boolean;
+      points: { t: number; c: number }[];
+    };
+    expect(series.enabled).toBe(true);
+    const sumBuckets = series.points.reduce((acc, p) => acc + p.c, 0);
+    const summary = buildUsageSummaryJson(24) as { totalEvents: number };
+    expect(sumBuckets).toBe(summary.totalEvents);
+  });
 });