gama-invoicelisted

# Invoice / Proforma Turn plain data into a correct, print-ready invoice. **Math must be exact.** ## Inputs the user should provide - Seller: name, address, tax/registration number - Buyer: name, address, tax/registration number - Invoice number, issue date, due date - Currency and VAT rate - Line items: description, quantity, unit, unit price (net or gross — ask which) - Payment details (IBAN, reference, payment method) If any of these are missing, ask **once**, in a single short list. Never guess tax numbers or account numbers. ## Calculation rules 1. Work **net** prices internally. If the user gives gross, back out net with `net = gross / (1 + vat)`. 2. Line total = `quantity × unit_price`. 3. Subtotal = sum of line totals. 4. VAT = `subtotal × vat_rate` (unless the invoice is exempt — then state the legal reason on the invoice). 5. Total = `subtotal + VAT`. 6. **Round to 2 decimals only at the end of each printed figure.** Round half-up. 7. Show the arithmetic: subtotal, VAT (rate), total. No hidden rounding. ## Output 1. A summary block: seller, buyer, number, dates, currency, VAT rate. 2. A line-items table: `# | description | qty | unit | unit price | line total`. 3. A totals block: Subtotal / VAT (x%) / **Total**. 4. Payment details. 5. Optional: a one-line "amount in words" if the user asks. ## Rules - Never invent a VAT rate — use the one the user gives, or the standard rate of the country the user names. - Mark a proforma clearly as **"PROFORMA — not a ta