fix(h3d): Creed re-check — shared-mutable-state setter pairs for 6 draw vars

THE BUG (silent, no throw): _drawNextByString, _drawRecentByString,
_drawChordTemplates, _drawAnchors, _drawTeachingMarks, _showFingerHints
were passed as plain-value shorthands to createRenderer. update() wrote
to those parameter locals; createNoteRenderer's getters read the original
screen.js closure vars — which never updated. drawNote saw stale null/false
on every frame.

THE FIX: converted all 6 to getter+setter DI pairs. update() calls
setDrawX(value); createNoteRenderer's existing get*() closures read
the same screen.js let vars. One store, no fork.

CLASS-KILLER GUARD (test 24): extracts all DI param names from the
createRenderer signature; scans module body (comments stripped) for
assignment operators on those names; asserts ZERO. RED at a55dca7
(6 assignments); GREEN here.

KILL TEST (test 28): overrides the 6 setter stubs in _makeDI() with
real backing-store vars; runs update() with a future note; asserts
backing store mutated from null sentinel. RED at a55dca7 (plain
assignment never called the setter; store stayed null). GREEN here.

ALSO (Toby r4 LOW): corrected smoke-test comment — reading an undeclared
variable throws ReferenceError in BOTH strict and sloppy mode; only WRITING
to undeclared differs (sloppy creates a global). The new Function sloppy
hole is for writes-only, not reads.

DI count: 321 (was 315, -6 shorthands +6 getters +6 setters).
Suite: 1408/1409 (test 46 pre-existing).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014uZ169yfoFYArXz962g7KW

plugins/highway_3d/screen.js

@@ -6984,13 +6984,26 @@ import { createRenderer } from './src/renderer.js'; // h3d-carve-15
             // ── Category C — fn-refs / let-vars ────────────────────────────────
             activePalette, anchorLaneBoundsAt, anchorPlayedFretSpanAt,
             boardSpanX, chordShapeSignature,
-            _drawAnchors, _drawChordTemplates, _drawNextByString, _drawRecentByString, _drawTeachingMarks,
+            // Shared-mutable-state pairs: update() writes via setters;
+            // createNoteRenderer's get* closures read the same screen.js lets.
+            getDrawAnchors: () => _drawAnchors,
+            setDrawAnchors: (v) => { _drawAnchors = v; },
+            getDrawChordTemplates: () => _drawChordTemplates,
+            setDrawChordTemplates: (v) => { _drawChordTemplates = v; },
+            getDrawNextByString: () => _drawNextByString,
+            setDrawNextByString: (v) => { _drawNextByString = v; },
+            getDrawRecentByString: () => _drawRecentByString,
+            setDrawRecentByString: (v) => { _drawRecentByString = v; },
+            getDrawTeachingMarks: () => _drawTeachingMarks,
+            setDrawTeachingMarks: (v) => { _drawTeachingMarks = v; },
+            getShowFingerHints: () => _showFingerHints,
+            setShowFingerHints: (v) => { _showFingerHints = v; },
             _encodeChordVerdictKey, _firstEventTimeGreaterThan,
             fretColumnMarkerCadence, fretColumnMarkersForAnchor, fretDividersVisible,
             fretLastActiveTime, _fretMarkerWaveCache, fretWireMats, fretX,
             getChartAnchorAt, hwyPostHitTailFadeMul,
             imFHTech, imFHXFill, imFHXLines, imPMTech, imPMXFill, imPMXLines,
-            laneBoundsFromAnchor, sectionLabelsOnHighway, _showFingerHints, updateStringHighlights,
+            laneBoundsFromAnchor, sectionLabelsOnHighway, updateStringHighlights,
             _noteKey,
             bendChevronMat, darkenHex, slideArrowMat, triMat,
             palmMuteXSpriteMat, fretHandMuteXSpriteMat,

plugins/highway_3d/src/renderer.js

@@ -112,13 +112,23 @@ export function createRenderer({
     // ── Category C — fn-refs / let-vars ──────────────────────────────────
     activePalette, anchorLaneBoundsAt, anchorPlayedFretSpanAt,
     boardSpanX, chordShapeSignature,
-    _drawAnchors, _drawChordTemplates, _drawNextByString, _drawRecentByString, _drawTeachingMarks,
+    // These 6 are the shared mutable state between update() (writer) and
+    // createNoteRenderer's drawNote (reader). Plain-value DI would fork the
+    // store — update() would write its local copy, drawNote would never see it.
+    // Setter pattern: renderer calls set*(); createNoteRenderer's existing
+    // get*() closures read the same screen.js let vars.
+    getDrawAnchors, setDrawAnchors,
+    getDrawChordTemplates, setDrawChordTemplates,
+    getDrawNextByString, setDrawNextByString,
+    getDrawRecentByString, setDrawRecentByString,
+    getDrawTeachingMarks, setDrawTeachingMarks,
+    getShowFingerHints, setShowFingerHints,
     _encodeChordVerdictKey, _firstEventTimeGreaterThan,
     fretColumnMarkerCadence, fretColumnMarkersForAnchor, fretDividersVisible,
     fretLastActiveTime, _fretMarkerWaveCache, fretWireMats, fretX,
     getChartAnchorAt, hwyPostHitTailFadeMul,
     imFHTech, imFHXFill, imFHXLines, imPMTech, imPMXFill, imPMXLines,
-    laneBoundsFromAnchor, sectionLabelsOnHighway, _showFingerHints, updateStringHighlights,
+    laneBoundsFromAnchor, sectionLabelsOnHighway, updateStringHighlights,
     _noteKey,
     bendChevronMat, darkenHex, slideArrowMat, triMat,
     palmMuteXSpriteMat, fretHandMuteXSpriteMat,
@@ -1073,12 +1083,12 @@ function update(bundle) {
         }
     }
 
-    _drawNextByString = nextNoteByString;
-    _drawChordTemplates = bundle.chordTemplates ?? null;
-    _drawAnchors = anchors ?? null;
-    _drawTeachingMarks = !!bundle.teachingMarksVisible;
+    setDrawNextByString(nextNoteByString);
+    setDrawChordTemplates(bundle.chordTemplates ?? null);
+    setDrawAnchors(anchors ?? null);
+    setDrawTeachingMarks(!!bundle.teachingMarksVisible);
     // Default on: only an explicit false (older bundles omit the flag) hides fg.
-    _showFingerHints = bundle.fingerHintsVisible !== false;
+    setShowFingerHints(bundle.fingerHintsVisible !== false);
 
     // ── Recent-past event per string (for _nextAnyT deadline) ─────
     // Once a note/chord passes `now` it leaves _drawNextByString,
@@ -1128,7 +1138,7 @@ function update(bundle) {
                 }
             }
         }
-        _drawRecentByString = _recArr;
+        setDrawRecentByString(_recArr);
     }
 
     // ── Sorted union of next/recent event times ──────────────────
@@ -1141,12 +1151,12 @@ function update(bundle) {
     // the recent-event prepass's inner-block ``_recArr`` alias.
     setScrEventTimesLen(0);
     for (let s = 0; s < nStr; s++) {
-        const nf = _drawNextByString[s];
+        const nf = getDrawNextByString()[s];
         if (nf) {
             const tn = nf.t;
             if (Number.isFinite(tn)) { const _etl = getScrEventTimesLen(); _scrEventTimes[_etl] = tn; setScrEventTimesLen(_etl + 1); }
         }
-        const rt = _drawRecentByString[s];
+        const rt = getDrawRecentByString()[s];
         if (Number.isFinite(rt)) { const _etl = getScrEventTimesLen(); _scrEventTimes[_etl] = rt; setScrEventTimesLen(_etl + 1); }
     }
     if (getScrEventTimesLen() > 1) {
@@ -2563,7 +2573,7 @@ function update(bundle) {
                 // stacked above the chord name. Gated by the
                 // teaching-marks opt-in (mirrors the 2D overlay). Display
                 // only — never grading.
-                if (_drawTeachingMarks && firstInShapeRun && !chordWireHighDensity(ch)) {
+                if (getDrawTeachingMarks() && firstInShapeRun && !chordWireHighDensity(ch)) {
                     const _tmpl = bundle.chordTemplates?.[ch.id];
                     const _h = chordHarmonyLabels(ch.fn, _tmpl?.voicing, _tmpl?.caged, _tmpl?.guideTones);
                     if (_h.rn || _h.voicing || _h.caged || _h.guideTones) {
@@ -2908,7 +2918,7 @@ function update(bundle) {
             const _fwA = Math.max(_fwE.a, _fwE.openA);
             if (_fwA <= 0) continue;
             let _w0 = -1, _w1 = -1;
-            const _fwB = anchorLaneBoundsAt(_drawAnchors, _fwE.t);
+            const _fwB = anchorLaneBoundsAt(getDrawAnchors(), _fwE.t);
             if (_fwB) {
                 _w0 = _fwB.dMin;
                 _w1 = _fwB.dMax;