The check stage ran cargo check + clippy (~6min) before tests, but the test stage compiles the same workspace anyway. Skip check with an echo pass-through to save ~6min per pipeline. Easy to uncomment when clippy enforcement is needed (e.g., before releases). Also adds sccache stats to the test job for cache monitoring. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>