fix: prevent asset conflicts between React and Grid.js versions

Add coexistence checks to all enqueue methods to prevent loading
both React and Grid.js assets simultaneously.

Changes:
- ReactAdmin.php: Only enqueue React assets when ?react=1
- Init.php: Skip Grid.js when React active on admin pages
- Form.php, Coupon.php, Access.php: Restore classic assets when ?react=0
- Customer.php, Product.php, License.php: Add coexistence checks

Now the toggle between Classic and React versions works correctly.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

node_modules/cssstyle/lib/utils/colorSpace.js

@@ -0,0 +1,21 @@
+'use strict';
+
+const hueToRgb = (t1, t2, hue) => {
+  if (hue < 0) hue += 6;
+  if (hue >= 6) hue -= 6;
+
+  if (hue < 1) return (t2 - t1) * hue + t1;
+  else if (hue < 3) return t2;
+  else if (hue < 4) return (t2 - t1) * (4 - hue) + t1;
+  else return t1;
+};
+
+// https://www.w3.org/TR/css-color-4/#hsl-to-rgb
+exports.hslToRgb = (hue, sat, light) => {
+  const t2 = light <= 0.5 ? light * (sat + 1) : light + sat - light * sat;
+  const t1 = light * 2 - t2;
+  const r = hueToRgb(t1, t2, hue + 2);
+  const g = hueToRgb(t1, t2, hue);
+  const b = hueToRgb(t1, t2, hue - 2);
+  return [Math.round(r * 255), Math.round(g * 255), Math.round(b * 255)];
+};

node_modules/cssstyle/lib/utils/getBasicPropertyDescriptor.js

@@ -0,0 +1,14 @@
+'use strict';
+
+module.exports = function getBasicPropertyDescriptor(name) {
+  return {
+    set: function(v) {
+      this._setProperty(name, v);
+    },
+    get: function() {
+      return this.getPropertyValue(name);
+    },
+    enumerable: true,
+    configurable: true,
+  };
+};