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/stoichiometry.js

@@ -199,6 +199,9 @@ class StoichSim {
 
   /* ── Выбрать рецепт ─────────────────────────────────────────────── */
   _setRecipe(idx) {
+    if (this._recipeIdx !== undefined && this._recipeIdx !== idx && window.LabFX) {
+      LabFX.sound.play('click', { pitch: 1.3 });
+    }
     this._recipeIdx = idx;
     const r = StoichSim.RECIPES[idx];
 
@@ -465,7 +468,14 @@ class StoichSim {
       };
     });
 
+    const prevLimitIdx = this._computed ? this._computed.limitIdx : -1;
     this._computed = { limitIdx, limitVal, ratios, reactantQ, productQ };
+
+    // LabFX: haptic + tick when limiting reagent changes
+    if (window.LabFX && prevLimitIdx !== limitIdx) {
+      LabFX.haptic(20);
+      LabFX.sound.play('tick', { pitch: 0.8, volume: 0.3 });
+    }
   }
 
   /* ── Правая панель: пошаговый расчёт ───────────────────────────── */
@@ -772,10 +782,29 @@ class StoichSim {
     this._animT     = 0;
     const dur = 1200; // ms
     const start = performance.now();
+    let lastTs = start;
+
+    // LabFX: fizz sound + bubble particles at reactant boxes
+    if (window.LabFX && this._ctx) {
+      LabFX.sound.play('fizz');
+      const W = this._canvas.offsetWidth || 300;
+      const H = this._canvas.offsetHeight || 200;
+      const r = StoichSim.RECIPES[this._recipeIdx];
+      r.reactants.forEach((re, i) => {
+        const x = (W / (r.reactants.length + 1)) * (i + 1);
+        LabFX.particles.emit({ ctx: this._ctx, x, y: H * 0.4, count: 8,
+          color: re.color || '#FFFFFF', speed: 35, spread: 2.5, angle: -Math.PI / 2,
+          gravity: -50, life: 800, shape: 'ring' });
+      });
+    }
 
     const tick = (now) => {
+      const dt = (now - lastTs) / 1000;
+      lastTs = now;
+      if (window.LabFX) LabFX.particles.update(dt);
       this._animT = Math.min(1, (now - start) / dur);
       this._draw();
+      if (window.LabFX && this._ctx) LabFX.particles.draw(this._ctx);
       if (this._animT < 1) {
         this._raf = requestAnimationFrame(tick);
       } else {