4 commits, squashed; the originals stay reachable from tag archive/merge-main-develop. -d3f771998jyviko: kernel-ladder: tier 07 corner cases grade their geometry -0d7acb0cejyviko: kernel-ladder: 08/007 grades the rounds run into the chamfer -c9dcc42a1jyviko: kernel-ladder: tier 09 shells grade their geometry -05e0dc17bjyviko: kernel-ladder: 10/008 grades the vents as four times one Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01DtL5M41G8Nua7HvuFPZkmJ