* tests : add README for updating the per-backend fusion baselines
Assisted-by: pi:llama.cpp/Qwen3.8-27B
* ci : trigger fusion on changes to test-llama-archs.cpp and src/models
the dummy models and their architectures drive the fusion baselines, so a
change to either can alter the per-fusion counters and should re-run the
fusion job.
Assisted-by: pi:llama.cpp/Qwen3.8-27B
* tests : merge the fusion build commands in the README
assisted-by: pi:llama.cpp/Qwen3.8-27B
* pi : require explicit permission before posting PR/issue comments
assisted-by: pi:llama.cpp/Qwen3.8-27B
