PERF.78 Code: dead modules and exports, god functions and cyclomatic hotspots beyond the mains

Confirmed dead: cadcraft addons/windows/lib/cutlist/cutlist.js (190 lines, a stale copy nothing imports), addons/trusscraft/lib/layout.js in four apps (tests only), modelcraft anim/skin-gpu.js, compute/parity.js twice, partcraft eng-data and eng-units stubs; 32 dead exports (about 54 KB: partcraft worker solvers, the openfoam runner) plus 26 orphan modules (about 141 KB). Name-level dead code across the 5,020 namespace and dynamic imports needs a bundler dry run (one tree-shake pass per app as a report, nothing shipped bundled). Hotspots: 120 functions over 300 lines and 618 with cyclomatic complexity 40 or more: readFamily 234, writeDwg 769 lines at 214 (plus convert 195, buildModelParts 182), vla-host get 207, validateItem 194, buildSite3D 190, dxf entityFrom0 187 and writeDxf 159, pdf-write writeMarkedUp 182, writeCivilIfc 702 lines, model-ui mountModel 1,804 lines, res-ui 1,407, shell app-panels 1,742 and app-settings 1,521. Change: table-driven dispatch for the entity switches, one module per panel section, delete the dead files; each behind the existing tests.