4.8.0

Included commits: 4.7.0...4.8.0

Improvements

• Added CurrencyReaderInterface::findByIsoCode() as a nullable alternative to getByIsoCode(), allowing callers to check currency existence without catching exceptions.
• Optimized CurrencyReader::getAllStoresWithCurrencies() to load all required currencies in a single query instead of one query per store.
• Changed CurrencyFacade::findCurrencyByIsoCode() to delegate to CurrencyReader::findByIsoCode() so the internal currency cache is used on repeated lookups.