445d6d7b6d
The Banana export assumed a double-entry file; a user importing into an Income & Expense (Einnahmen-Ausgaben) file got "AccountDebit/AccountCredit/Amount/ VatCode column not found", since those columns only exist in double-entry. Add a second Banana format alongside the double-entry one: - ledgerService: new `banana_ie` format → Banana I&E columns Date, Doc, Description, Income, Expenses, ContraAccount (the income/expense account), VatCode (banana.ch doc 9946). Revenue → gross in Income + revenue account; cost → gross in Expenses + expense account. Same tab-separated .txt shape. - Frontend: ExportFormat + dropdown gain `banana_ie`; .txt extension covers both Banana variants. Labels relabelled: "Banana — double-entry" and "Banana — income & expense" (de equivalents). Hint de-"double-entry"-fied. - Test added for the I&E format. Pairs with the prior UTF-8 BOM fix (the "·" mojibake). Tests + build green.