fix(labs): SVG markup rendered as text in 6 simulations

Hardcoded inline <svg class="ic"> markers used as arrow replacements

(left over from emoji removal) were displayed as raw HTML text where

the consumer used textContent or canvas fillText:

- chemsandbox: csbar-v5 (Продукты cell) used textContent → SVG visible.

  Switched to innerHTML for consistency with eq/ionNet cells.

  Quiz question (qEl.textContent) and answer also receiving SVG —

  cleaned via _csClean at source.

- reactions: modeTxt drawn via canvas fillText — replaced SVG with →.

- ionexchange: REACTIONS data + canvas labels — bulk SVG → Unicode arrows.

- newton: action button labels used textContent → switched to innerHTML;

  canvas arrow labels: SVG → Unicode →/↓.

- collision: 'KE сохранена' canvas label — SVG checkmark → ✓.

- projectile: canvas badges + textContent wind label — SVG → Unicode ←/→/↩.

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

frontend/js/labs/newton.js

@@ -277,7 +277,7 @@ class NewtonSim {
     }
   }
 
-  /* ── Физика I-B : орбита <svg class="ic" viewBox="0 0 24 24"><line x1="5" y1="12" x2="19" y2="12"/><polyline points="12 5 19 12 12 19"/></svg> прямолинейное движение ────────── */
+  /* ── Физика I-B : орбита → прямолинейное движение ────────── */
 
   _step1B(dt) {
     const s = this._1B;
@@ -804,10 +804,10 @@ class NewtonSim {
       const alpha = Math.min(1, s.forceFlash * 2.5);
       const fScale = 72 * alpha;
       const ny = g.gY - CH - 32;
-      /* Сила на ядро <svg class="ic" viewBox="0 0 24 24"><line x1="5" y1="12" x2="19" y2="12"/><polyline points="12 5 19 12 12 19"/></svg> вправо */
-      this._arrow(ctx, s.cx + CW / 2 + 20, ny, s.cx + CW / 2 + 20 + fScale, ny, '#EF476F', 'F<svg class="ic" viewBox="0 0 24 24"><line x1="5" y1="12" x2="19" y2="12"/><polyline points="12 5 19 12 12 19"/></svg>ядро', 2.5);
-      /* Реакция на пушку <svg class="ic" viewBox="0 0 24 24"><line x1="5" y1="12" x2="19" y2="12"/><polyline points="12 5 19 12 12 19"/></svg> влево */
-      this._arrow(ctx, s.cx - CW / 2 - 20, ny, s.cx - CW / 2 - 20 - fScale, ny, '#4CC9F0', 'F<svg class="ic" viewBox="0 0 24 24"><line x1="5" y1="12" x2="19" y2="12"/><polyline points="12 5 19 12 12 19"/></svg>пушка', 2.5);
+      /* Сила на ядро → вправо */
+      this._arrow(ctx, s.cx + CW / 2 + 20, ny, s.cx + CW / 2 + 20 + fScale, ny, '#EF476F', 'F→ядро', 2.5);
+      /* Реакция на пушку → влево */
+      this._arrow(ctx, s.cx - CW / 2 - 20, ny, s.cx - CW / 2 - 20 - fScale, ny, '#4CC9F0', 'F→пушка', 2.5);
 
       ctx.save(); ctx.globalAlpha = alpha;
       ctx.font = 'bold 12px sans-serif'; ctx.fillStyle = '#FFD166';
@@ -990,7 +990,7 @@ class NewtonSim {
     }
     /* Falling after fuel out — show gravity arrow */
     if (s.fuel <= 0 && !s.stopped) {
-      this._arrow(ctx, rx, ry + 25, rx, ry + 65, '#EF476F', 'mg<svg class="ic" viewBox="0 0 24 24"><line x1="12" y1="5" x2="12" y2="19"/><polyline points="19 12 12 19 5 12"/></svg>', 2.5);
+      this._arrow(ctx, rx, ry + 25, rx, ry + 65, '#EF476F', 'mg↓', 2.5);
       ctx.font = 'bold 13px sans-serif'; ctx.fillStyle = '#EF476F';
       ctx.textAlign = 'center'; ctx.fillText('Топливо кончилось — ракета падает!', W / 2, H * 0.15); ctx.textAlign = 'left';
     }
@@ -1009,7 +1009,7 @@ class NewtonSim {
       ctx.textAlign = 'center'; ctx.fillText('Нажмите «Запуск» для включения двигателя', W / 2, H * 0.50); ctx.textAlign = 'left';
     }
 
-    this._caption(ctx, 'Газ вниз <svg class="ic" viewBox="0 0 24 24"><line x1="5" y1="12" x2="19" y2="12"/><polyline points="12 5 19 12 12 19"/></svg> ракета вверх\n(3-й закон Ньютона)', W, H);
+    this._caption(ctx, 'Газ вниз → ракета вверх\n(3-й закон Ньютона)', W, H);
   }
 
   /* ── Вспомогательные рисовалки ──────────────────────────── */
@@ -1350,8 +1350,8 @@ function _nwt_lighten(hex, d) {
 
     // action button label
     const lbl = sceneData.action || (law === 1 ? '<svg class="ic" viewBox="0 0 24 24"><circle cx="6" cy="6" r="3"/><circle cx="6" cy="18" r="3"/><line x1="20" y1="4" x2="8.12" y2="15.88"/><line x1="14.47" y1="14.48" x2="20" y2="20"/><line x1="8.12" y1="8.12" x2="12" y2="12"/></svg> Нить' : '<svg class="ic" viewBox="0 0 24 24"><polygon points="5 3 19 12 5 21 5 3"/></svg> Действие');
-    document.getElementById('newton-action-label').textContent = lbl;
-    document.getElementById('newton-action-top').textContent = lbl;
+    document.getElementById('newton-action-label').innerHTML = lbl;
+    document.getElementById('newton-action-top').innerHTML = lbl;
 
     // show/hide sliders
     document.getElementById('newton-mu-block').style.display    = law === 1 && scene === 'A' ? '' : 'none';