Chore: uthash update and buffer overflow found

[Piloalucard]

Summary of changes

This pull request includes following changes or fixes.

• Updates uthash.h header to latest version available in master https://github.com/troydhanson/uthash/commits/master/src/uthash.h
  commit 41c357fd74ade4f4b4822c4407d2f51c4558e18d
• Added an extra comparison to prevent a memcpy with a negative count causing buffer overflow (Found with static analyzer)

Type of change

• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have confirmed my fix is effective or that my feature works

[Piloalucard]

For testing, created a bash script to automatize common tests of files and directories, and different usages of ltfsck and mkltfs.

Testing script: test_ltfs_build.sh
Test passed using file-backend:
ltfs_test_log_20260209_185930.log