feat(h3d-carve-14): extract V-section (note renderer) into src/note-renderer.js

Carve cut 14 of the h3d-carve epic. Moves the full V-section (note renderer):
  drawNote, drawArpBrackets, drawNotedetectLabels, chordHarmonyLabels
  and 14 private helpers (~1,433 lines)
from screen.js into plugins/highway_3d/src/note-renderer.js
as a factory-DI ES module: createNoteRenderer({137 DI params}).

Beyond-subst (3 sites):
  _ndVerdictSawAlpha = true  → setNdVerdictSawAlpha(true)
  _ndVerdictMaxAlpha = v     → setNdVerdictMaxAlpha(v)
  _streakHits = 0/++         → setStreakHits(0/getStreakHits()+1)

Tests:
  - New: tests/js/highway_3d_note_renderer.test.js (22 assertions)
    wiring guard (137 params), export contract, chordHarmonyLabels
    behavioral kills, beyond-subst sentinel, tombstone checks
  - Updated 8 existing test files to search note-renderer.js
    alongside screen.js for moved patterns (h3d-carve-14 retarget)

Bumps plugin.json 3.49.0 → 3.50.0

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

tests/js/highway_3d_lean_sustain.test.js

@@ -19,6 +19,10 @@ const fs = require('node:fs');
 const path = require('node:path');
 
 const SCREEN_JS = path.join(__dirname, '..', '..', 'plugins', 'highway_3d', 'screen.js');
+// h3d-carve-14: sustain trail code moved to note-renderer.js; trail tests
+// must now search both files.
+const NOTE_RENDERER_JS = path.join(__dirname, '..', '..', 'plugins', 'highway_3d', 'src', 'note-renderer.js');
+const _noteRendererSrc = fs.readFileSync(NOTE_RENDERER_JS, 'utf8');
 
 test('lean sustain rendering is the default (_leanSus starts true)', () => {
     const src = fs.readFileSync(SCREEN_JS, 'utf8');
@@ -57,7 +61,8 @@ test('exactly one element is gated behind the lean flag, and it is the rail bloo
 });
 
 test('the trail + ribbon outline always draw and use the hit/miss-aware material', () => {
-    const src = fs.readFileSync(SCREEN_JS, 'utf8');
+    // h3d-carve-14: sustain trail body now in note-renderer.js
+    const src = fs.readFileSync(SCREEN_JS, 'utf8') + '\n' + _noteRendererSrc;
     // Outline material is hit/miss aware: miss -> mMissOutline, confirmed hit
     // -> bright, otherwise the default mSusOutline white border.
     assert.match(