This commit refactors the SuperKmer extraction functionality to use Go's new iterator pattern. The ExtractSuperKmers function is now implemented as a wrapper around a new IterSuperKmers iterator function, which yields results one at a time instead of building a complete slice. This change provides better memory efficiency and more flexible consumption of super k-mers. The functionality remains the same, but the interface is now more idiomatic and efficient for large datasets.
