feat: SprintStatusDonut + getSprintStatusBreakdown helper

PieChart (donut) met TO_DO/IN_PROGRESS/DONE verdeling over alle active sprints.
REVIEW wordt samengevoegd in IN_PROGRESS. MD3 status-kleuren via CSS-variabelen.

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

app/(app)/insights/components/sprint-status-donut.tsx

@@ -0,0 +1,48 @@
+'use client'
+
+import { PieChart, Pie, Cell, Tooltip, Legend, ResponsiveContainer } from 'recharts'
+import type { StatusCount } from '@/lib/insights/sprint-status'
+
+interface Props {
+  data: StatusCount[]
+}
+
+const STATUS_COLORS: Record<string, string> = {
+  TO_DO: 'var(--status-todo)',
+  IN_PROGRESS: 'var(--status-in-progress)',
+  DONE: 'var(--status-done)',
+}
+
+const STATUS_LABELS: Record<string, string> = {
+  TO_DO: 'To do',
+  IN_PROGRESS: 'In progress',
+  DONE: 'Done',
+}
+
+export function SprintStatusDonut({ data }: Props) {
+  if (data.length === 0) {
+    return <p className="text-muted-foreground text-sm">Geen actieve sprint-taken</p>
+  }
+
+  const labeled = data.map(d => ({ ...d, name: STATUS_LABELS[d.status] ?? d.status }))
+
+  return (
+    <ResponsiveContainer width="100%" height={240}>
+      <PieChart>
+        <Pie
+          data={labeled}
+          dataKey="count"
+          nameKey="name"
+          innerRadius={50}
+          outerRadius={80}
+        >
+          {labeled.map(entry => (
+            <Cell key={entry.status} fill={STATUS_COLORS[entry.status]} />
+          ))}
+        </Pie>
+        <Tooltip />
+        <Legend />
+      </PieChart>
+    </ResponsiveContainer>
+  )
+}

lib/insights/sprint-status.ts

@@ -0,0 +1,39 @@
+import { prisma } from '@/lib/prisma'
+import { productAccessFilter } from '@/lib/product-access'
+
+export type SprintStatusGroup = 'TO_DO' | 'IN_PROGRESS' | 'DONE'
+
+export interface StatusCount {
+  status: SprintStatusGroup
+  count: number
+}
+
+// Maps REVIEW → IN_PROGRESS so donut shows 3 buckets only
+function toGroup(status: string): SprintStatusGroup {
+  if (status === 'DONE') return 'DONE'
+  if (status === 'TO_DO') return 'TO_DO'
+  return 'IN_PROGRESS'
+}
+
+export async function getSprintStatusBreakdown(userId: string): Promise<StatusCount[]> {
+  const tasks = await prisma.task.findMany({
+    where: {
+      story: {
+        sprint: {
+          status: 'ACTIVE',
+          product: productAccessFilter(userId),
+        },
+      },
+    },
+    select: { status: true },
+  })
+
+  const counts: Record<SprintStatusGroup, number> = { TO_DO: 0, IN_PROGRESS: 0, DONE: 0 }
+  for (const t of tasks) {
+    counts[toGroup(t.status)]++
+  }
+
+  return (Object.entries(counts) as [SprintStatusGroup, number][])
+    .filter(([, count]) => count > 0)
+    .map(([status, count]) => ({ status, count }))
+}