E-commerce Product Catalog Cleaning Instructions:

- Normalize all prices to float format (no currency symbols)
- Convert all dates to ISO 8601 format (YYYY-MM-DD)
- Fix category spelling and normalize to Title Case
- Standardize SKU format to uppercase with "SKU-" prefix
- Convert all weights to kilograms as float
- Ensure stock_quantity is a non-negative integer
- Strip HTML tags from descriptions, decode HTML entities
- Normalize brand names to Title Case
- Trim whitespace and fix double spaces
- Convert tags to arrays, remove duplicates, lowercase all
