The Mech ctor fully constructs (33 subsystems / 7 weapons on real TEST.EGG data,
trace-confirmed). The crash is the control-mapping resource binding in
MakeViewpointEntity resolving subsystem attribute IDs via GetAttributePointer --
the subsystems publish none (reuse base AttributeIndex). Documented the precise
phase-5 step-1 scope (per-subsystem AttributeIndex + the ID chain) in MECH.NOTES.md.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>