feat: upgrade llama.cpp to b6047

[zwpaper]

fix windows build: https://github.com/TabbyML/tabby/actions/runs/16651099664

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 55.13%. Comparing base (56661ba) to head (8510e7f).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4330   +/-   ##
=======================================
  Coverage   55.12%   55.13%           
=======================================
  Files         235      235           
  Lines       26878    26878           
=======================================
+ Hits        14816    14818    +2     
+ Misses      12062    12060    -2     

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