E10 — Motion-Model Correctness

[sobechestnut-dev]

Epic for the motion-model correctness fixes carved out of DD-009 §3 into DD-010 (Accepted 2026-07-24, D1–D6 revised for firmware correctness).

Unlike E9's additive/opt-in surfaces, these alter existing IR output (position/extrusion semantics), so each phase carries an explicit golden-regeneration + capability-honesty strategy (DD-010 D5) and downstream re-validation.

Children (from the #154 audit)

• fix(parser): honor M82/M83 extruder absolute-relative mode #156 M82/M83 extruder absolute/relative mode (highest impact) — D1
• fix(parser): honor G90/G91 absolute-relative positioning + G92 offset #155 G90/G91 positioning + G92 offset — D2 (mode) + D4 (offset)
• fix(parser): honor G17/G18/G19 arc-plane selection #157 G17/G18/G19 arc-plane selection — D3
• fix(parser): honor G53/G54–G59 coordinate systems #158 G53/G54–G59 coordinate systems — D4

Phases (DD-010 §14, impact-first)

1. Modal machinery — M82/M83 + G90/G91 + G92 E-datum (firmware-conditioned; generic mode→channel seam). Capabilities extrusionMode, positioningMode.
2. Arc planes — G17/G18/G19. Capability arcPlanes.
3. Coordinate systems — G53/G54–G59 + G92 XYZ. Capability coordinateSystem.

Sibling DDs that depend on this one (scoped, not merged): .bgcode decode (#188 → DD-011), CNC/laser move-model (#189 → DD-012). The DD-010 modal-channel seam is shared with #180.