Refactor kmer index to disk-based partitioning with minimizer

Refactor kmer index package to use disk-based partitioning with minimizer

- Replace roaring64 bitmaps with disk-based kmer index
- Implement partitioned kmer sets with delta-varint encoding
- Add support for frequency filtering during construction
- Introduce new builder pattern for index construction
- Add streaming operations for set operations (union, intersect, etc.)
- Add support for super-kmer encoding during construction
- Update command line tool to use new index format
- Remove dependency on roaring bitmap library

This change introduces a new architecture for kmer indexing that is more memory efficient and scalable for large datasets.

pkg/obikmer/kmer_set_group.go

@@ -145,6 +145,14 @@ func (ksg *KmerSetGroup) AddSequences(sequences *obiseq.BioSequenceSlice, index
 	ksg.sets[index].AddSequences(sequences)
 }
 
+// AddSequenceSlice adds all k-mers from a slice of sequences to a specific KmerSet
+func (ksg *KmerSetGroup) AddSequenceSlice(sequences *obiseq.BioSequenceSlice, index int) {
+	if index < 0 || index >= len(ksg.sets) {
+		panic(fmt.Sprintf("Index out of bounds: %d (size: %d)", index, len(ksg.sets)))
+	}
+	ksg.sets[index].AddSequenceSlice(sequences)
+}
+
 // Union returns the union of all KmerSet in the group
 // Optimization: starts from the largest set to minimize operations
 func (ksg *KmerSetGroup) Union() *KmerSet {