refactor(admin): split dsr page.tsx into colocated components

Extract TabNavigation, StatCard, RequestCard, FilterBar, DSRCreateModal,
DSRDetailPanel, DSRHeaderActions, and banner components (LoadingSpinner,
SettingsTab, OverdueAlert, DeadlineInfoBox, EmptyState) into _components/
so page.tsx drops from 1019 to 247 LOC (under the 300 soft target).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

admin-compliance/app/sdk/dsr/_components/DSRHeaderActions.tsx

@@ -0,0 +1,35 @@
+'use client'
+
+export function DSRHeaderActions({
+  onOpenCreate,
+}: {
+  onOpenCreate: () => void
+}) {
+  return (
+    <div className="flex items-center gap-2">
+      <button
+        onClick={() => {
+          const link = document.createElement('a')
+          link.href = '/api/sdk/v1/compliance/dsr/export?format=csv'
+          link.download = 'dsr_export.csv'
+          link.click()
+        }}
+        className="flex items-center gap-2 px-4 py-2 text-gray-600 bg-gray-100 hover:bg-gray-200 rounded-lg transition-colors"
+      >
+        <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+          <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M4 16v1a3 3 0 003 3h10a3 3 0 003-3v-1m-4-4l-4 4m0 0l-4-4m4 4V4" />
+        </svg>
+        CSV Export
+      </button>
+      <button
+        onClick={onOpenCreate}
+        className="flex items-center gap-2 px-4 py-2 bg-purple-600 text-white rounded-lg hover:bg-purple-700 transition-colors"
+      >
+        <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+          <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 6v6m0 0v6m0-6h6m-6 0H6" />
+        </svg>
+        Anfrage erfassen
+      </button>
+    </div>
+  )
+}