feat(labs): visual polish wave — LabFX foundation + 33 sims juiced up

ФУНДАМЕНТ (4 новых файла):
- _fx_core.js: LabFX namespace, glow.drawGlow, glow.pulse, haptic, shake
- _fx_particles.js: пул 1500 объектов, 6 shapes (dot/spark/ring/smoke/splash/dust)
- _fx_motion.js: tween + 12 easings + critically-damped spring
- _fx_sound.js: 9 procedural synth-звуков (click/tick/whoosh/chime/fizz/spark/bounce/pour/drone), Web Audio API
- Sound toggle в шапке lab.html с localStorage-persist

UX МИКРО (CSS + JS):
- Button states: hover scale+brightness, active scale-down, disabled grayscale
- Slider polish: custom thumb с тенью, filled-track gradient, hover/active
- Focus rings через :focus-visible
- Tooltip system .tt-host data-tt= с 400ms hover, fade-in
- Marching ants для selection
- Loading skeleton с shimmer
- Empty state .sim-empty-* паттерн
- Toast: progress bar внизу, icons по типу
- Cursor states utility classes
- View Transitions API для smooth sim-switch, fallback на CSS fade

PHASE 2 — визуальные эффекты для 33 симуляций:

Physics motion: projectile (launch whoosh + landing splash/shake/haptic + target chime), pendulum (max-extension tick + bob glow), collision (bounce + sparks + shake), angrybirds (whoosh/bounce/fizz/chime + confetti), newton (rocket flame trail + scene transitions), forcesandbox (spring glow + impact sparks)

Physics fields: emfield (field-lines glow + particle trail + lightning при high field + Gauss-drag haptic + rod motion sparks), circuit (energized-wire glow ∝ current + LED bloom + short-circuit shake/spark + heat shimmer smoke + place/erase/switch sounds), opticsbench (beam glow на всех режимах + caustics dust у фокуса + TIR/Brewster one-shot sounds)

Thermo+waves: waves (mode-switch whoosh + Mach-cone particles + spectrum harmonic chime + waveform glow), hydrostatics (pour sound + splash при погружении + valve click), isoprocess (PV-trail dust), heatengine (drone цикла + hot/cold reservoir smoke/dust + phase-change ticks), radioactive (Geiger tick throttle + decay sparks + half-life chime + α/β/γ glow)

Chemistry: chemsandbox (pour splash + fizz bubbles/dust/spark по типу реакции + shake при горении), equilibrium/electrolysis/reactions/titration/flask/ionexchange/redox (pour/fizz/spark/chime по событиям, частицы при ключевых моментах), stoichiometry (fizz bubbles + recipe-change click)

Math+geom: geometry (tool-click + object-create tick + locus glow + challenge confetti via LabFX + haptic), triangle (vertex-drop tick + special-point glow), stereo (figure-change whoosh + cross-section chime, no particles — Three.js), trigcircle (drag-haptic + pitch∝angle tick + sin/cos glow), graph/graphtransform/quadratic (slider-tick throttled + curve glow + discriminant-cross chime), probability (bounce + finish-chime burst), normaldist (pulsing shade + bell glow)

Bio+misc: celldivision (phase-change whoosh + prophase dust + anaphase poles spark + cytokinesis chime), photosynthesis (photon tick + ATP chime + glucose sparkle), bohratom (electron-jump chime ∝ levels + photon spark), orbitals/crystal (mode-change whoosh — Three.js, sound only), logic (gate-place + wire-connect + LED bloom + HIGH wire flowing dots + preset chime), gas/brownian/diffusion/states (preset whoosh, throttled tick по событиям)

Все LabFX вызовы обёрнуты в if (window.LabFX) guard — graceful degradation если фундамент не загружен. 47 JS файлов прошли syntax check.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/js/labs/brownian.js

@@ -20,6 +20,7 @@ class BrownianSim {
     this._raf      = null;
     this.onUpdate  = null;
     this._dpr      = 1;
+    this._fxLastT  = 0;
 
     // v2
     this._msdHistory = [];  // [{step, msd}]
@@ -93,8 +94,11 @@ class BrownianSim {
   stop()  { if (this._raf) { cancelAnimationFrame(this._raf); this._raf = null; } }
 
   // ── simulation ──────────────────────────────────────────────────────────────
-  _loop() {
+  _loop(now) {
+    const dt = this._fxLastT ? Math.min(now - this._fxLastT, 80) : 16;
+    this._fxLastT = now;
     this._step(); this._step(); this._step();
+    if (window.LabFX) LabFX.particles.update(dt);
     this.draw();
     this._raf = requestAnimationFrame(this._loop.bind(this));
   }
@@ -305,6 +309,7 @@ class BrownianSim {
 
     // Hover tooltip
     if (this._hover) this._drawBigTooltip(ctx, W, H);
+    if (window.LabFX) LabFX.particles.draw(ctx);
   }
 
   _drawMsdChart(ctx, W, H) {