refactor: distribute lab-init.js into 34 engine files

lab-init.js: 4098 -> 543 lines (infrastructure + THEORY only)

Each sim's _open*() + UI helpers moved to its engine file:
graph.js, projectile.js, collision.js, magnetic.js, triangle.js,
geometry.js, trigcircle.js, gas.js (molphys), coulomb.js, circuit.js,
reactions.js (chemistry), newton.js (dynamics), chemsandbox.js,
celldivision.js, photosynthesis.js, angrybirds.js, quadratic.js,
normaldist.js, graphtransform.js, pendulum.js, equilibrium.js,
thinlens.js, mirror.js, isoprocess.js, titration.js, refraction.js,
probability.js, bohratom.js, electrolysis.js, waves.js,
crystal.js, orbitals.js, stereo.js, hydrostatics.js

All 34 engine files syntax-checked OK.

frontend/js/labs/photosynthesis.js

@@ -1,4 +1,4 @@
-'use strict';
+'use strict';
 /* ════════════════════════════════════════════════════════════════
    PhotosynthesisSim — Фотосинтез и клеточное дыхание
    Световые реакции · цикл Кальвина · митохондриальное дыхание
@@ -809,3 +809,53 @@ function _psRRect(ctx, x, y, w, h, r) {
   ctx.arcTo(x, y, x + w, y, r);
   ctx.closePath();
 }
+
+/* ─── lab UI init ─────────────────────────────────── */
+  function _openPhotosynthesis(mode) {
+    document.getElementById('sim-topbar-title').textContent = 'Фотосинтез и дыхание';
+    _simShow('sim-photosynthesis');
+    _simShow('ctrl-photosynthesis');
+    requestAnimationFrame(() => requestAnimationFrame(() => {
+      const canvas = document.getElementById('photosyn-canvas');
+      if (!photosynSim) {
+        photosynSim = new PhotosynthesisSim(canvas);
+        photosynSim.onUpdate = _psUpdateUI;
+      }
+      photosynSim.fit();
+      photosynSim.setMode(mode || 'photo');
+      photosynSim.start();
+    }));
+  }
+
+  function psSetMode(mode, btn) {
+    document.querySelectorAll('.ps-mode-btn').forEach(b => b.classList.remove('active'));
+    if (btn) btn.classList.add('active');
+    if (photosynSim) photosynSim.setMode(mode);
+  }
+
+  function psLightChange() {
+    const v = +document.getElementById('sl-ps-light').value;
+    document.getElementById('ps-light-val').textContent = v + '%';
+    if (photosynSim) photosynSim.setLightIntensity(v);
+  }
+
+  function psCO2Change() {
+    const v = +document.getElementById('sl-ps-co2').value;
+    document.getElementById('ps-co2-val').textContent = v + '%';
+    if (photosynSim) photosynSim.setCO2(v);
+  }
+
+  function psReset() {
+    if (photosynSim) photosynSim.reset();
+  }
+
+  function _psUpdateUI(info) {
+    const v = (id, val) => { const el = document.getElementById(id); if (el) el.textContent = val; };
+    v('psbar-v1', info.atpRate || '0');
+    v('psbar-v2', info.o2 || '0');
+    v('psbar-v3', info.co2 || '0');
+    v('psbar-v4', info.efficiency ? info.efficiency + '%' : '—');
+    v('psbar-v5', info.mode === 'photo' ? 'Фотосинтез' : 'Дыхание');
+  }
+
+  /* ── Angry Birds ── */