Upgrade llama.cpp from b9437 to b9442

[bernardladenthin]

Summary

• Bumps llama.cpp dependency from b9437 to b9442
• Updates documentation to reflect new pinned version across CMakeLists.txt, README.md, and CLAUDE.md
• Adds breaking changes log entry documenting five additive/behavioral changes in the upstream range:
  • New whitespace tokenizer pre-type and normalizer lowercase support in vocab/arch
  • iGPU device collection fix to prevent duplicates on multi-iGPU hosts
  • UI webasset embedder format specifier tightening and CSS injection support
  • Python-side GGUF writer helpers for whitespace tokenizer and lowercase normalizer

Test plan

• CI is green on this branch
• Docs / CHANGELOG updated where applicable

Related issues / PRs

Checklist

• I have read CONTRIBUTING.md and CODE_OF_CONDUCT.md
• My commits follow Conventional Commits
• No security-sensitive changes (if there are, I have notified the maintainer privately per SECURITY.md)

https://claude.ai/code/session_01FQtvT2cR14QLFfqx2eLfpN

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud