Add governed source freshness audit

frontend/src/hooks/useSourceFreshness.ts

@@ -0,0 +1,46 @@
+import { useCallback, useEffect, useRef, useState } from 'react'
+
+import { datasetsApi } from '../services/api'
+import type { SourceFreshnessReport } from '../types'
+
+export function useSourceFreshness(selectedProjectId: string | null) {
+  const [report, setReport] = useState<SourceFreshnessReport | null>(null)
+  const [loading, setLoading] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+  const requestSequence = useRef(0)
+
+  const refresh = useCallback(async () => {
+    const requestId = ++requestSequence.current
+    if (!selectedProjectId) {
+      setReport(null)
+      setError(null)
+      setLoading(false)
+      return
+    }
+    setLoading(true)
+    setError(null)
+    try {
+      const nextReport = await datasetsApi.sourceFreshness(selectedProjectId)
+      if (requestSequence.current === requestId) {
+        setReport(nextReport)
+      }
+    } catch (caught) {
+      if (requestSequence.current === requestId) {
+        setError(caught instanceof Error ? caught.message : 'De broncontrole kon niet worden geladen.')
+      }
+    } finally {
+      if (requestSequence.current === requestId) {
+        setLoading(false)
+      }
+    }
+  }, [selectedProjectId])
+
+  useEffect(() => {
+    void refresh()
+    return () => {
+      requestSequence.current += 1
+    }
+  }, [refresh])
+
+  return { report, loading, error, refresh }
+}