CI runs 'make check' = dependency-free tests, no model downloads (by design,
#140). glm_tiny/ is a gitignored generated fixture, so test_inefficiency.py
hard-failed on the Windows/macOS/Linux runners with 'config.json: No such file
or directory' instead of skipping.
_engine_present() now requires BOTH glm.exe AND glm_tiny/config.json, and
_skip_reason() names exactly which prerequisite is missing so the skip is
actionable. Verified: 8 skipped (0 failed) with the fixture absent; 5 pass +
3 CUDA-skip with it present.
woolcoxm
cf126cbcf9