PERF.74 Code: shared utilities written hundreds of times: vector math 2,088 implementations, csv cell 431, point-in-polygon 243, esc 198, uid 188, download 163

tools/perf/quality-utils.mjs counted 6,943 implementations of 24 utility names (21,260 lines): vector math 2,088 (516 distinct bodies in 1,094 files), area 299, point-in-polygon 243 (identical clusters of 17, 12, 9, 8 and 6), bbox 190, lerp 69, clamp 68; text and bytes: esc 198, uid 188, download/saveBlob 163, csv cell 431, base64 59. The shell exports none of these; lib/units is the one shared table that is used everywhere. Change: lib/geom2d (vec, bbox, area, point-in-polygon, lerp, clamp) and a shell util.js (esc, uid, download, csv, base64) synced into the builds like host.js; mechanical replacement guided by the cluster list, with the quality scripts kept as the check so the count only goes down. Also shell-mount.js (a 48-line block identical in seven apps) and ui-util.js (eight variants of one 45 to 76 line file) become synced shell files, and the Studio Live stateCore plus diff and invert hand-copied in three apps and joinFromPage in six become a shell live-state.js.