Financial Transaction Records Cleaning Instructions:

- Normalize amounts to float (remove currency symbols, commas)
- Convert all dates to ISO 8601 format (YYYY-MM-DD)
- Standardize time to 24-hour format (HH:MM:SS)
- Normalize currency codes to 3-letter uppercase (USD, EUR, GBP)
- Standardize transaction_type to uppercase (DEBIT, CREDIT, TRANSFER)
- Normalize status to lowercase (completed, pending, failed)
- Clean merchant names: Title Case, trim whitespace
- Mask account numbers consistently as ****XXXX (last 4 digits)
- Standardize country codes to 2-letter ISO format (US, GB, CA)
- Normalize fee to float, convert "N/A" to 0.0
- Standardize reference numbers with "REF-" prefix
- Clean descriptions: proper casing, fix whitespace, remove truncation markers
