Columns: station_name, address, fuel_rate, amount, date, time, customer_name, vehicle_number, vehicle_type, payment_type, receipt_number, template, logo
vehicle_type: Petrol | Diesel | CNG | Electric
payment_type: Cash | Online | Debit Card
template: 1 | 2 | 3 (optional, falls back to default)
logo: bharat-petroleum | indian-oil | hp | essar-oil (optional, default: bharat-petroleum)
date: YYYY-MM-DD   time: HH:MM (24h)