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/webpack/schemas/plugins/BannerPlugin.json

@@ -0,0 +1,115 @@
+{
+  "definitions": {
+    "BannerFunction": {
+      "description": "The banner as function, it will be wrapped in a comment.",
+      "instanceof": "Function",
+      "tsType": "import('../../lib/BannerPlugin').BannerFunction"
+    },
+    "Rule": {
+      "description": "Filtering rule as regex or string.",
+      "anyOf": [
+        {
+          "instanceof": "RegExp",
+          "tsType": "RegExp"
+        },
+        {
+          "type": "string",
+          "minLength": 1
+        },
+        {
+          "instanceof": "Function",
+          "tsType": "import('../../lib/ModuleFilenameHelpers').MatcherFn"
+        }
+      ]
+    },
+    "Rules": {
+      "description": "Filtering rules.",
+      "anyOf": [
+        {
+          "type": "array",
+          "items": {
+            "description": "A rule condition.",
+            "oneOf": [
+              {
+                "$ref": "#/definitions/Rule"
+              }
+            ]
+          }
+        },
+        {
+          "$ref": "#/definitions/Rule"
+        }
+      ]
+    }
+  },
+  "title": "BannerPluginArgument",
+  "anyOf": [
+    {
+      "description": "The banner as string, it will be wrapped in a comment.",
+      "type": "string",
+      "minLength": 1
+    },
+    {
+      "title": "BannerPluginOptions",
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "banner": {
+          "description": "Specifies the banner.",
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "$ref": "#/definitions/BannerFunction"
+            }
+          ]
+        },
+        "entryOnly": {
+          "description": "If true, the banner will only be added to the entry chunks.",
+          "type": "boolean"
+        },
+        "exclude": {
+          "description": "Exclude all modules matching any of these conditions.",
+          "oneOf": [
+            {
+              "$ref": "#/definitions/Rules"
+            }
+          ]
+        },
+        "footer": {
+          "description": "If true, banner will be placed at the end of the output.",
+          "type": "boolean"
+        },
+        "include": {
+          "description": "Include all modules matching any of these conditions.",
+          "oneOf": [
+            {
+              "$ref": "#/definitions/Rules"
+            }
+          ]
+        },
+        "raw": {
+          "description": "If true, banner will not be wrapped in a comment.",
+          "type": "boolean"
+        },
+        "stage": {
+          "description": "Specifies the stage when add a banner.",
+          "type": "number"
+        },
+        "test": {
+          "description": "Include all modules that pass test assertion.",
+          "oneOf": [
+            {
+              "$ref": "#/definitions/Rules"
+            }
+          ]
+        }
+      },
+      "required": ["banner"]
+    },
+    {
+      "$ref": "#/definitions/BannerFunction"
+    }
+  ]
+}