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/spdy-transport/lib/spdy-transport.js

@@ -0,0 +1,25 @@
+'use strict'
+
+var transport = exports
+
+// Exports utils
+transport.utils = require('./spdy-transport/utils')
+
+// Export parser&framer
+transport.protocol = {}
+transport.protocol.base = require('./spdy-transport/protocol/base')
+transport.protocol.spdy = require('./spdy-transport/protocol/spdy')
+transport.protocol.http2 = require('./spdy-transport/protocol/http2')
+
+// Window
+transport.Window = require('./spdy-transport/window')
+
+// Priority Tree
+transport.Priority = require('./spdy-transport/priority')
+
+// Export Connection and Stream
+transport.Stream = require('./spdy-transport/stream').Stream
+transport.Connection = require('./spdy-transport/connection').Connection
+
+// Just for `transport.connection.create()`
+transport.connection = transport.Connection