Moves 7 exports from screen.js to a new ES module src/geometry.js:
geoFretX (was fretX, now 2-arg), dZ, slideTrailEnd, camBaseDistU,
camLowFretPullbackU, computeBPM, _makeGaussTex.
Internal helpers _fretXLog / _fretXUniStep / _fretXUni are module-private
inside geometry.js. Module-level constants (SCALE, K, FRET_SCALE, NFRETS,
FRET_SPACING_*, TS) are duplicated at geometry.js module scope — values
are compile-time and never vary at runtime.
screen.js keeps a 1-arg delegator (1 beyond-subst):
const fretX = f => geoFretX(f, _h3dFretUniform);
No call site changes; fretMid / fretColumnWorldW / slideOffsetWorldX /
_recomputeFretSpacingDerived stay in screen.js and use the delegator.
Tests:
- highway_3d_geometry.test.js: class-killer via import() with 9
known-answer assertions (geoFretX uniform/log invariants, dZ linearity,
slideTrailEnd, computeBPM BPM estimate).
- highway_3d_fret_spacing: test updated to match delegator pattern + adds
GEOMETRY_JS read to verify geoFretX export.
- highway_3d_sustain_bloom: retargeted _makeGaussTex check to GEOMETRY_JS
(definition moved); call-site check stays on SCREEN_JS.
- highway_3d_panel_controls: vm loader strips ES import line and injects
geometry stubs; all factory-statics tests unaffected.
Suite: 169/169 pass
node --test tests/js/highway_3d*.test.js plugins/highway_3d/tests/*.test.js
Version bump: 3.35.0 -> 3.36.0
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014uZ169yfoFYArXz962g7KW
