CJ engineering-review mesh source notices

CJ preserves the visible six-point star, R1.85 luminous hex and CI carrier
envelope. The bottom diffuser pocket now stops at Z18.70, leaving a continuous
0.70 mm metal roof below the visible face. This closes all six former radial
through-slots; only the central hex passes through. The diffuser remains
bottom-insertable through a rounded lower body with a central hex light column,
and the constructed carrier contains no undercut.

This review contains tessellated display assets, not fabrication files or a
manufacturing release. Cutter selection, workholding, coating allowance,
tolerances, real leakage and supplier DFM remain unapproved.

EC60 basis: https://github.com/4pplet/EC60 commit b9c04625bb9944f6fb806aa571da8592cdff8565 (MIT).