Skip fewer attention blocks on early steps and more on late ones, in a straight line up to sla_sparsity. Off at 0, untested on H3. Credit GSRS (arXiv 2610.21129). tools/test_env.sh and tools/cpuforce.py set up the suite on a GPU-less machine. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_0176SHndmQj7T1VtWAWZiNcq