feat(runtime): résout react/react-dom vers l'instance host pour les layouts plugin

Le runtime SDK expose désormais react/react-dom résolus contre l'instance
hébergée par IdeA plutôt qu'une copie embarquée, pour que les layouts plugin
en JSX/hooks partagent le même arbre React que l'host. hello-plugin migre son
layout d'exemple en .tsx pour illustrer le contrat.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

package-lock.json

@@ -9,9 +9,74 @@
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+        "react-dom": "^18.2.0 || ^19.0.0"
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+      "license": "MIT",
+      "dependencies": {
+        "csstype": "^3.2.2"
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+    "node_modules/@types/react-dom": {
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+      "license": "MIT",
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+    "node_modules/react-dom": {
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+      "license": "MIT",
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+      "dev": true,
+      "license": "MIT"
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     "node_modules/typescript": {
       "version": "5.9.3",
       "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.9.3.tgz",