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/data-urls/lib/parser.js

@@ -0,0 +1,69 @@
+"use strict";
+const MIMEType = require("whatwg-mimetype");
+const { parseURL, serializeURL, percentDecodeString } = require("whatwg-url");
+const { stripLeadingAndTrailingASCIIWhitespace, isomorphicDecode, forgivingBase64Decode } = require("./utils.js");
+
+module.exports = stringInput => {
+  const urlRecord = parseURL(stringInput);
+
+  if (urlRecord === null) {
+    return null;
+  }
+
+  return module.exports.fromURLRecord(urlRecord);
+};
+
+module.exports.fromURLRecord = urlRecord => {
+  if (urlRecord.scheme !== "data") {
+    return null;
+  }
+
+  const input = serializeURL(urlRecord, true).substring("data:".length);
+
+  let position = 0;
+
+  let mimeType = "";
+  while (position < input.length && input[position] !== ",") {
+    mimeType += input[position];
+    ++position;
+  }
+  mimeType = stripLeadingAndTrailingASCIIWhitespace(mimeType);
+
+  if (position === input.length) {
+    return null;
+  }
+
+  ++position;
+
+  const encodedBody = input.substring(position);
+
+  let body = percentDecodeString(encodedBody);
+
+  // Can't use /i regexp flag because it isn't restricted to ASCII.
+  const mimeTypeBase64MatchResult = /(.*); *[Bb][Aa][Ss][Ee]64$/u.exec(mimeType);
+  if (mimeTypeBase64MatchResult) {
+    const stringBody = isomorphicDecode(body);
+    body = forgivingBase64Decode(stringBody);
+
+    if (body === null) {
+      return null;
+    }
+    mimeType = mimeTypeBase64MatchResult[1];
+  }
+
+  if (mimeType.startsWith(";")) {
+    mimeType = `text/plain${mimeType}`;
+  }
+
+  let mimeTypeRecord;
+  try {
+    mimeTypeRecord = new MIMEType(mimeType);
+  } catch (e) {
+    mimeTypeRecord = new MIMEType("text/plain;charset=US-ASCII");
+  }
+
+  return {
+    mimeType: mimeTypeRecord,
+    body
+  };
+};

node_modules/data-urls/lib/utils.js

@@ -0,0 +1,18 @@
+"use strict";
+const { atob } = require("abab");
+
+exports.stripLeadingAndTrailingASCIIWhitespace = string => {
+  return string.replace(/^[ \t\n\f\r]+/u, "").replace(/[ \t\n\f\r]+$/u, "");
+};
+
+exports.isomorphicDecode = input => {
+  return Array.from(input, byte => String.fromCodePoint(byte)).join("");
+};
+
+exports.forgivingBase64Decode = data => {
+  const asString = atob(data);
+  if (asString === null) {
+    return null;
+  }
+  return Uint8Array.from(asString, c => c.codePointAt(0));
+};