feat(frontend): Export-Buttons fuer Voelker, Honigchargen (Modul 21)

CSV-Export in den Listen-Views (Voelker, Honigchargen) und
PDF-Rueckverfolgbarkeitsbericht auf der Honigcharge-Detailseite.
apiFetchBlob() im API-Client ergaenzt fuer authentifizierte
Blob-Downloads (JWT im Authorization-Header statt Cookie).

ApiCore-Frontend/src/lib/export/api.ts

@@ -0,0 +1,33 @@
+import { apiFetchBlob } from "@/lib/auth/api-client";
+
+export function downloadBlob(blob: Blob, filename: string): void {
+  const url = URL.createObjectURL(blob);
+  const link = document.createElement("a");
+  link.href = url;
+  link.download = filename;
+  document.body.appendChild(link);
+  link.click();
+  document.body.removeChild(link);
+  URL.revokeObjectURL(url);
+}
+
+export async function exportColoniesCsv(): Promise<void> {
+  const { blob, filename } = await apiFetchBlob("/export/colonies.csv", "colonies.csv");
+  downloadBlob(blob, filename);
+}
+
+export async function exportHoneyBatchesCsv(): Promise<void> {
+  const { blob, filename } = await apiFetchBlob(
+    "/export/honey-batches.csv",
+    "honey-batches.csv",
+  );
+  downloadBlob(blob, filename);
+}
+
+export async function exportHoneyBatchTraceabilityPdf(honeyBatchId: string): Promise<void> {
+  const { blob, filename } = await apiFetchBlob(
+    `/export/honey-batch-traceability.pdf?honeyBatchId=${honeyBatchId}`,
+    "honey-batch-traceability.pdf",
+  );
+  downloadBlob(blob, filename);
+}