feat: add toolbox contract shell and testkit

examples/react-app/src/App.tsx

@@ -0,0 +1,19 @@
+import { AppShell } from "@add-ideas/toolbox-shell-react";
+import "@add-ideas/toolbox-shell-react/styles.css";
+
+import { toolboxApp } from "./toolbox-app.js";
+
+export function App() {
+  return (
+    <AppShell app={toolboxApp} appActions={<a href="./help/">Help</a>}>
+      <section>
+        <h2>Ready</h2>
+        <p>
+          Open this app directly for standalone mode, or add
+          <code>?toolbox=/toolbox.catalog.json</code> to connect it to a
+          same-origin catalog.
+        </p>
+      </section>
+    </AppShell>
+  );
+}

examples/react-app/src/main.tsx

@@ -0,0 +1,13 @@
+import { StrictMode } from "react";
+import { createRoot } from "react-dom/client";
+
+import { App } from "./App.js";
+
+const root = document.querySelector("#root");
+if (!root) throw new Error("Missing #root element");
+
+createRoot(root).render(
+  <StrictMode>
+    <App />
+  </StrictMode>,
+);

examples/react-app/src/toolbox-app.ts

@@ -0,0 +1,33 @@
+import { defineToolboxApp } from "@add-ideas/toolbox-contract";
+
+export const toolboxApp = defineToolboxApp({
+  schemaVersion: 1,
+  id: "de.add-ideas.example-tool",
+  name: "Example Tool",
+  version: "0.1.0",
+  description: "A minimal toolbox-compatible React application.",
+  entry: "./",
+  icon: "./icon.svg",
+  categories: ["examples"],
+  tags: ["react", "toolbox"],
+  integration: {
+    contextVersion: 1,
+    launchModes: ["navigate", "new-tab"],
+    embedding: "unsupported",
+  },
+  requirements: {
+    secureContext: false,
+    workers: false,
+    indexedDb: false,
+    crossOriginIsolated: false,
+  },
+  privacy: {
+    processing: "local",
+    fileUploads: false,
+    telemetry: false,
+  },
+  source: {
+    repository: "https://git.add-ideas.de/zemion/toolbox-sdk",
+    license: "Apache-2.0",
+  },
+});