Add jj Makefile targets and k-mer encoding utilities

Add new Makefile targets for jj operations (jjnew, jjpush, jjfetch) to streamline commit workflow.

Introduce k-mer encoding utilities in pkg/obikmer:
- EncodeKmers: converts DNA sequences to encoded k-mers
- ReverseComplement: computes reverse complement of k-mers
- NormalizeKmer: returns canonical form of k-mers
- EncodeNormalizedKmers: encodes sequences with normalized k-mers

Add comprehensive tests for k-mer encoding functions including edge cases, buffer reuse, and performance benchmarks.

Document k-mer index design for large genomes, covering:
- Use cases and objectives
- Volume estimations
- Distance metrics (Jaccard, Sørensen-Dice, Bray-Curtis)
- Indexing options (Bloom filters, sorted sets, MPHF)
- Optimization techniques (k-2-mer indexing)
- MinHash for distance acceleration
- Recommended architecture for presence/absence and counting queries

Makefile

@@ -108,5 +108,27 @@ ifneq ($(strip $(COMMIT_ID)),)
 	@rm -f $(OUTPUT)
 endif
 
-.PHONY: all obitools update-deps obitests githubtests .FORCE
+jjnew:
+	@echo "$(YELLOW)→ Creating a new commit...$(NC)"
+	@echo "$(BLUE)→ Documenting current commit...$(NC)"
+	@jj auto-describe
+	@echo "$(BLUE)→ Done.$(NC)"
+	@jj new
+	@echo "$(GREEN)✓ New commit created$(NC)"
+
+jjpush: 
+	@echo "$(YELLOW)→ Pushing commit to repository...$(NC)"
+	@echo "$(BLUE)→ Documenting current commit...$(NC)"
+	@jj auto-describe
+	@echo "$(BLUE)→ Done.$(NC)"
+	@jj git push --change @
+	@echo "$(GREEN)✓ Commit pushed to repository$(NC)"
+
+jjfetch:
+	@echo "$(YELLOW)→ Pulling latest commits...$(NC)"
+	@jj git fetch
+	@jj new master@origin
+	@echo "$(GREEN)✓ Latest commits pulled$(NC)"
+
+.PHONY: all obitools update-deps obitests githubtests jjnew jjpush jjfetch .FORCE
 .FORCE: