Add CAMTParser (ISO 20022) alongside MT940; accept both formats

- New CAMTParser project: namespace-agnostic parser for camt.052/053/054
  producing a statement/entry model aligned with the banking columns
  (account, amount, debit/credit, dates, counterparty, references, remittance).
- BankingService now auto-detects the upload format (XML→CAMT, else MT940)
  and maps either into the same fds__tt__bankingtransactions DataTable, so the
  bam/up handler transparently accepts both.
- Frontend (fis.bam.de.js) upload field now advertises accept for both
  MT940 (.sta/.mt940/.txt) and CAMT (.xml/.camt).
- Tests (+14, 151 total): CamtParserTests cover parsing (credit/debit,
  namespace-version agnostic, reversals), detection, and failure/edge inputs
  (empty, invalid XML, non-CAMT); BankingDualFormatTests verify CAMT and MT940
  both land in the same DataTable.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Fuchs/wwwroot/web/fis.bam.de.js

@@ -36,7 +36,8 @@ let $bcol = {
         { name: 'EndToEndReference', label: 'Referenz', type: 'string' }
     ]),
     bsu: new fields_definition('Kontobericht', 'Kontoberichte', [
-        { name: 'bsu', label: 'Export der Buchungen', type: 'file', required: true, prop: { multiple: true } }
+        // Accepts both MT940 (SWIFT text: .sta/.mt940/.txt) and CAMT (ISO 20022 XML: .xml/.camt).
+        { name: 'bsu', label: 'Export der Buchungen (MT940 oder CAMT)', type: 'file', required: true, prop: { multiple: true, accept: '.sta,.mt940,.txt,.xml,.camt,application/xml,text/xml,text/plain' } }
     ])
 };
 let gi = (n, c) => $$.sc(`glyphicon glyphicon-${n}`).aC(c);