Agent throughput: jobs per dag stacked bar + KPI-strip (#49)

* feat(insights): add getJobsPerDay helper — agent throughput per day + KPIs

Raw SQL aggregation of claude_jobs by day and status over 14 days with
zero-fill for missing days. KPIs: todayCount, successRate7d, avgDurationSeconds7d.
Optional productId filter.

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

* feat(insights): add AgentThroughputCard — stacked BarChart + KPI-strip + product filter

KPI strip (jobs today, 7d success rate, 7d avg duration), 14-day stacked
BarChart with JOB_STATUS_COLORS, and URL-bookmarkable product dropdown via
useTransition + router.replace. Empty-state when no activity.

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

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

__tests__/lib/insights/agent-throughput.test.ts

@@ -0,0 +1,82 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+
+const { mockQueryRaw } = vi.hoisted(() => ({ mockQueryRaw: vi.fn() }))
+
+vi.mock('@/lib/prisma', () => ({
+  prisma: { $queryRaw: mockQueryRaw },
+}))
+
+import { getJobsPerDay } from '@/lib/insights/agent-throughput'
+
+// Build a date string for N days ago (UTC)
+function daysAgo(n: number): Date {
+  const d = new Date()
+  d.setUTCDate(d.getUTCDate() - n)
+  return d
+}
+
+function toUTCDate(d: Date): Date {
+  return new Date(Date.UTC(d.getUTCFullYear(), d.getUTCMonth(), d.getUTCDate()))
+}
+
+beforeEach(() => {
+  vi.clearAllMocks()
+})
+
+describe('getJobsPerDay', () => {
+  it('returns a 14-day array zero-filled for missing days', async () => {
+    // Only 3 days have data; the rest should be 0
+    const day0 = toUTCDate(daysAgo(0))
+    const day3 = toUTCDate(daysAgo(3))
+    const day7 = toUTCDate(daysAgo(7))
+
+    const dayRows = [
+      { day: day0, status: 'done', count: BigInt(2) },
+      { day: day3, status: 'failed', count: BigInt(1) },
+      { day: day7, status: 'done', count: BigInt(5) },
+    ]
+
+    const kpiRows = [
+      { today_count: BigInt(2), done_7d: BigInt(7), terminal_7d: BigInt(10), avg_seconds: 120 },
+    ]
+
+    mockQueryRaw.mockResolvedValueOnce(dayRows).mockResolvedValueOnce(kpiRows)
+
+    const result = await getJobsPerDay('user-1')
+
+    expect(result.perDay).toHaveLength(14)
+
+    // All days should have zero counts except the three we seeded
+    const nonZero = result.perDay.filter(
+      d => d.done + d.failed + d.queued + d.claimed + d.running + d.cancelled > 0,
+    )
+    expect(nonZero).toHaveLength(3)
+
+    // Today's done count should be 2
+    const today = result.perDay[result.perDay.length - 1]
+    expect(today.done).toBe(2)
+  })
+
+  it('calculates KPIs correctly', async () => {
+    mockQueryRaw.mockResolvedValueOnce([]).mockResolvedValueOnce([
+      { today_count: BigInt(3), done_7d: BigInt(7), terminal_7d: BigInt(10), avg_seconds: 90 },
+    ])
+
+    const result = await getJobsPerDay('user-1')
+
+    expect(result.kpi.todayCount).toBe(3)
+    expect(result.kpi.successRate7d).toBe(0.7)
+    expect(result.kpi.avgDurationSeconds7d).toBe(90)
+  })
+
+  it('returns zero successRate and null avgDuration when no terminal jobs', async () => {
+    mockQueryRaw.mockResolvedValueOnce([]).mockResolvedValueOnce([
+      { today_count: BigInt(0), done_7d: BigInt(0), terminal_7d: BigInt(0), avg_seconds: null },
+    ])
+
+    const result = await getJobsPerDay('user-1')
+
+    expect(result.kpi.successRate7d).toBe(0)
+    expect(result.kpi.avgDurationSeconds7d).toBeNull()
+  })
+})