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/async-function/package.json

@@ -0,0 +1,86 @@
+{
+	"name": "async-function",
+	"version": "1.0.0",
+	"description": "A function that returns the normally hidden `AsyncFunction` constructor",
+	"main": "./legacy.js",
+	"jsnext:main": "./index.mjs",
+	"module": "./index.mjs",
+	"exports": {
+		".": [
+			{
+				"module-sync": "./require.mjs",
+				"import": "./index.mjs",
+				"default": "./index.js"
+			},
+			"./index.js"
+		],
+		"./package.json": "./package.json"
+	},
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"prepublishOnly": "safe-publish-latest",
+		"pretest": "npm run --silent lint",
+		"test": "npm run tests-only",
+		"posttest": "npx npm@\">=10.2\" audit --production",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"prelint": "evalmd README.md",
+		"lint": "eslint --ext=js,mjs .",
+		"postlint": "tsc && attw -P",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/ljharb/async-function.git"
+	},
+	"keywords": [
+		"async",
+		"await",
+		"function",
+		"native"
+	],
+	"author": "Jordan Harbamd <ljharb@gmail.com>",
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/async-function/issues"
+	},
+	"homepage": "https://github.com/ljharb/async-function#readme",
+	"devDependencies": {
+		"@arethetypeswrong/cli": "^0.17.3",
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.2.3",
+		"@types/semver": "^6.2.7",
+		"@types/tape": "^5.8.1",
+		"auto-changelog": "^2.5.0",
+		"eslint": "=8.8.0",
+		"evalmd": "^0.0.19",
+		"get-proto": "^1.0.1",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"safe-publish-latest": "^2.0.0",
+		"semver": "^6.3.1",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"engines": {
+		"node": ">= 0.4"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"testling": {
+		"files": "test/index.js"
+	}
+}