Ruled 2026-10-07 (Captain Bob): POST on every node, nodes without
storage, and block requests passed from node to node had left v3's
design. MESH.md section 8 is rewritten: a block is a kernel request, as
ENGINE.md 3.3 already had it; every node has blocks; there is one chain.
Private drives and the message device are withdrawn, and listed in 8.5
so that they are not proposed again. Acceptance 1 and 3 change with it.
A born node is not POSTed, and the kernel is to hold POST's cases.
The plan for step 6 is revised to match.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>