Check numbers in DeskCalc

Show numbers as a labelled adding-machine tape in DeskCalc so the user can check every line, correct it and press Confirm. Returns the confirmed total, the lines, the user's corrections and - if you pass the printed figures - a cent-exact check of the document. Use it before you rely on a sum you extracted from receipts, statements or invoices. If the result is "pending", tell the user to finish the check in DeskCalc and call get_verification with the review_id. Line kinds: (1) amount: {label, value}. (2) quantity x unit price: {label, qty, price, value?} - value is the printed line total, checked against qty x price. (3) VAT/sales tax: {type:"tax", rate, included?, value?} - put it after the taxable lines; DeskCalc computes the tax from the subtotal above and recomputes it when the user corrects a line; value is the printed tax amount; included=true for gross prices ("incl. VAT"). (4) discount/surcharge in percent on the subtotal above: {type:"percent", rate, value?} - rate -3 for "3 % Rabatt", -2 for "2 % Skonto", +5 for a surcharge; value is the printed amount. A DISCOUNT ON A SINGLE POSITION ("Rabatt"/"Disc." column): {label, qty, price, discount: 10, value: printed line total} - discount in percent; DeskCalc shows qty x price and the discount below it, the check compares the printed line total. Never derive the discount from the printed total. Prices per 100/1000 units: convert to a unit price or give the line total as an amount. (5) MIXED TAX RATES (e.g. 20 % and 10 % on one invoice): a tax line always applies to the whole subtotal above, so put the positions of each rate in their own group: {type:"group", label:"20 %"}, its positions, its tax line; then {type:"group", label:"10 %"}, ... DeskCalc adds a GT (grand total) line. If the result has gt_outdated=true (the user corrected a line, the GT line is a snapshot), call verify_numbers again with exactly the arguments in "rerun" and use that second result. (6) MANY RECEIPTS (expenses, a stack of bills): ONE call, ONE tape - one amount line per receipt (label "14.10. Hotel"), never one call per receipt. If the receipts print their VAT, ALWAYS give each receipt its own group: the gross amount, then its tax line with included=true and the PRINTED VAT as value - only then can a misprinted VAT be found (the GT is still the total of the receipts). If an expense report prints a total, pass it as expected_total. (7) PRINTED SUBTOTALS / CARRY-OVERS (bank statement, ledger over several pages, "Übertrag", "Zwischensumme"): {type:"subtotal", label:"Übertrag S.1", value} at that place - DeskCalc shows the running total there and the check names the first carry-over that is wrong. An opening balance is a normal amount line. (8) CROSS-FOOTING A TABLE (net, tax, gross columns): one line per row {label, value: gross, net, tax} and nothing else in that call; pass expected_total (gross column total), expected_net_total and expected_tax_total if printed (row_labels: omit - the tape uses DeskCalc's language). DeskCalc shows each row as its own block: net, tax, and the printed gross as a checkpoint. (9) FOREIGN CURRENCY: {label, foreign: 100, currency:"USD", fx_rate: 0.92, value: 92.00} - fx_rate is home currency per 1 unit; if the document quotes the inverse (1 EUR = 1.08 USD), give the printed home amount as a plain amount line and name the rate in the label. For invoices also pass expected_total (the printed amount payable). After a confirmed check, offer save_audit_record (PDF for the working papers); to reconcile two documents (invoice vs delivery note, order or payment), verify both, then call compare_verifications. If you use a figure that is NOT printed on the document (e.g. a fee from a published table, a rate you looked up), say so in the label, e.g. "(Tab. A, web)", and tell the user - the tape must not make your own assumptions look like the document. Numbers: plain, "." as decimal separator, negative for credits. Labels: SHORT, max ~25 characters, e.g. "Pos.1 Wandfarbe" or "14.10. Hotel" - longer labels are cut off on the tape. Title: 1-3 words; it becomes the tab name in DeskCalc.