feat(drum_highway_3d): materials & themes — studio env map, metal cymbals, BG_THEMES, cinematic, glow/vibrancy (D3) (#712)

- _makeStudioEnv: procedural PMREM environment (no RoomEnvironment addon
  vendored) -> scene.environment; rebuilt on kit-change, disposed both
  teardown paths
- Cymbals roughness 0.2 / metalness 0.85 / envMapIntensity 1.2 (metal
  finally reads); discs satin 0.45 + envInt 0.5; floor 0.7 + envInt 0.35;
  hit bar envInt 1.0
- BG_THEMES port (guitar ids/values; drum 'default' = original palette
  byte-for-byte; single pick drives clear/fog + board + lane stripes);
  drumH3dSetTheme + drum_h3d_bg_theme; live _applyTheme
- Cinematic lighting toggle (0.3/1.2 on, 0.4/1.0 off = stock)
- Glow slider (base * glow*2; 0.5 default = stock) across notes/hit
  bar/snare stripe; Lane vibrancy slider (stripe base 0.12+0.24v +
  halo/ghost opacities), stacking under the D2 approach highlight
- Fixed pre-existing floor/hit-bar geometry+material leak on kit change
- Tests: theme table parity + default preservation + fallbacks (13)

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

plugins/drum_highway_3d/tests/data_layer.test.js

@@ -115,3 +115,36 @@ test('FX defaults: hit-FX controls ship enabled', () => {
     assert.equal(FX_DEFAULTS.streakFx, true);
     assert.equal(FX_DEFAULTS.hitFx, 0.7);
 });
+
+test('themes: table ids match the guitar highway, default is the stock palette', () => {
+    const { BG_THEMES, _bgThemeColors } = load().__test;
+    // Same id set as highway_3d's BG_THEMES (cross-instrument consistency).
+    assert.deepEqual(Object.keys(BG_THEMES), [
+        'default', 'midnight', 'charcoal', 'deeppurple', 'forest', 'warmslate',
+        'deepfocus', 'deepsea', 'cathode', 'cathodegreen', 'hearth',
+    ]);
+    // 'default' preserves THIS plugin's original look byte-for-byte.
+    assert.equal(BG_THEMES.default.clear, 0x1a1a2e);
+    assert.equal(BG_THEMES.default.board, 0x0a0e1a);
+    assert.equal(BG_THEMES.default.lane, undefined); // stock stripes fallback
+    // Unknown ids fall back to default.
+    assert.equal(_bgThemeColors('nonsense'), BG_THEMES.default);
+    // Every non-default theme carries a lane pair (the axis differentiator).
+    for (const [id, t] of Object.entries(BG_THEMES)) {
+        if (id === 'default') continue;
+        assert.ok(t.lane != null && t.laneDim != null, id + ' lane pair');
+        assert.equal(t.clear, t.fog, id + ' clear==fog (horizon dissolve)');
+    }
+});
+
+test('readThemeSetting: defaults without localStorage; validates ids', () => {
+    const { readThemeSetting } = load().__test;
+    assert.equal(readThemeSetting(), 'default');
+});
+
+test('FX defaults: theme-PR controls ship enabled at stock-neutral values', () => {
+    const { FX_DEFAULTS } = load().__test;
+    assert.equal(FX_DEFAULTS.cinematic, true);
+    assert.equal(FX_DEFAULTS.glow, 0.5);      // 0.5 = 1.0x multiplier (stock)
+    assert.equal(FX_DEFAULTS.vibrancy, 0.85); // ≈ the stock 0.32 stripe base
+});