PERF.73 Code: copies that drifted and hand copies with no sync tool (six inflate implementations, xlsx.js in four variants, input-mouse.js in eight apps)

The byte-copy system works where a tool owns the copy (1,011 of 1,043 copy groups). Outside it: inflateRaw plus deflateZlib byte-identical in lib/3dm and lib/chip, six inflate implementations in lib and crc32 in 316 files (one lib/zip); xlsx.js six times in four hand-edited variants (one lib/xlsx); pdf-snap.js and takeoffcraft snap.js diverged; lib/walls ahead of bimcraft wall-square.js (two solvers for one wall); 31 drifted file pairs in all; whole-file hand copies with no tool: input-mouse.js in eight apps, wheel-pad.js in five, panes.js in three, params.js, framing.js, bcf.js, render-tools.js, carbon-factors.js, keynotes.js; CadCraft's m3d copy stale because its tool refuses to run (FX.143). Change: one owner per copy (lib/ or the shell) with a sync tool, and bin/test-sync-copies.mjs that runs every sync tool with --check (130 tools; some write without the flag: give them one first). Also the STEP string helpers S/E/L/B typed into five IFC writers (civilcraft three, detailcraft, partcraft) belong in lib/ifc/step.js.