Mellow 0.4.1-dev — 7D41 evidence tooling

0.4.1-dev adds explicit native-Xe backend readiness diagnostics plus verifiable public-Metal compute and offscreen-render acceptance tools for 8086:7D41. The kext is structurally built and Tahoe 25G83 import eligibility is recorded, but this is not a hardware-validated Metal driver. GitHub Actions did not start because the account is billing-locked; no native macOS CI result exists for this tag. See docs/ACCEPTANCE-0.4.1.ko.md and docs/NATIVE-XE-BACKEND-AUDIT.md.