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.go

@@ -82,6 +82,13 @@ func (ks *KmerSet) AddSequences(sequences *obiseq.BioSequenceSlice) {
 	}
 }
 
+// AddSequenceSlice adds all k-mers from a slice of sequences
+func (ks *KmerSet) AddSequenceSlice(sequences *obiseq.BioSequenceSlice) {
+	for _, seq := range *sequences {
+		ks.AddSequence(seq)
+	}
+}
+
 // Contains checks if a k-mer is in the set
 func (ks *KmerSet) Contains(kmer uint64) bool {
 	return ks.bitmap.Contains(kmer)