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/lab-glue.js

@@ -966,6 +966,35 @@
     }
   };
 
+  /* ─── Sim Fade Transition + View Transitions API ─────────────────────────
+     Wraps openSim with a fade-out (150ms) → swap → fade-in (200ms) sequence.
+     If document.startViewTransition is available it is used for GPU-composited
+     cross-fade; otherwise the manual .sim-fading CSS class is toggled.
+     The hash-router wrap above runs synchronously during the transition so URL
+     updates are not delayed.
+  ──────────────────────────────────────────────────────────────────────── */
+  var _hashRouterOpenSim = openSim; // reference after hash-router wrap
+  openSim = function(id) {
+    var labSim = document.getElementById('lab-sim');
+    if (!labSim) { _hashRouterOpenSim(id); return; }
+
+    function _doSwitch() {
+      labSim.classList.add('sim-fading');
+      setTimeout(function() {
+        _hashRouterOpenSim(id);
+        labSim.classList.remove('sim-fading');
+      }, 150);
+    }
+
+    if (typeof document.startViewTransition === 'function' && !_embedMode) {
+      document.startViewTransition(function() {
+        _hashRouterOpenSim(id);
+      });
+    } else {
+      _doSwitch();
+    }
+  };
+
   // Intercept closeSim to clear hash when returning to home grid
   var _origCloseSim = closeSim;
   closeSim = function() {