feat(export): Bestandsbuch für Tierarzneimittel nach Art. 108 VO (EU) 2019/6

- Treatment records supplier, purchase proof and prescribing vet, and
  keeps the apiary the colony stood at on the treatment day.
- Holder name and address in site settings (never in public output;
  regression test in public.service.spec).
- treatment-log.pdf: one sheet per apiary, identical treatments grouped,
  missing mandatory fields printed as FEHLT, uncertain locations marked.
- Shared PDF table helpers extracted from the record card.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

ApiCore-Backend/test/export.e2e-spec.ts

@@ -184,6 +184,19 @@ describe('Export (e2e)', () => {
       .expect(404);
   });
 
+  it('renders the Bestandsbuch for a year, also when nothing was treated', async () => {
+    for (const query of ['year=2026', 'year=1999']) {
+      const response = await request(app.getHttpServer())
+        .get(`/api/v1/export/treatment-log.pdf?${query}`)
+        .set('Authorization', `Bearer ${beekeeperToken}`)
+        .expect(200);
+      expect(response.headers['content-type']).toContain('application/pdf');
+      expect(
+        (response.body as Buffer).subarray(0, 4).toString('latin1'),
+      ).toBe('%PDF');
+    }
+  });
+
   it('rejects the apiary annual report without an apiaryId', () => {
     return request(app.getHttpServer())
       .get('/api/v1/export/apiary-annual-report.pdf')