Fix super k-mer minimizer bijection and add validation test

This commit addresses a bug in the super k-mer implementation where the minimizer bijection property was not properly enforced. The fix ensures that:

1. All k-mers within a super k-mer share the same minimizer
2. Identical super k-mer sequences have the same minimizer

The changes include:

- Fixing the super k-mer iteration logic to properly validate the minimizer bijection property
- Adding a comprehensive test suite (TestSuperKmerMinimizerBijection) that validates the intrinsic property of super k-mers
- Updating the .gitignore file to properly track relevant files

This resolves issues where the same sequence could be associated with different minimizers, violating the super k-mer definition.

.gitignore

@@ -27,7 +27,8 @@ xx
 
 !/obitests/**
 !/sample/**
-LLM/** 
+LLM/**
 *_files
 
-entropy.html
+entropy.html
+bug_id.txt