feat: complete TASK-WP0-01 toolchain skeleton

apps/web/src/main.tsx

@@ -0,0 +1,16 @@
+import { StrictMode } from "react";
+import { createRoot } from "react-dom/client";
+
+import { ToolchainProbe } from "./toolchain-probe.js";
+
+const root = document.getElementById("root");
+
+if (!root) {
+  throw new Error("Dada web root element is missing.");
+}
+
+createRoot(root).render(
+  <StrictMode>
+    <ToolchainProbe />
+  </StrictMode>,
+);

apps/web/src/toolchain-probe.tsx

@@ -0,0 +1,21 @@
+import { Rect, version as fabricVersion } from "fabric";
+import { renderToStaticMarkup } from "react-dom/server";
+
+export function ToolchainProbe() {
+  return <canvas aria-label="Dada toolchain probe" height={16} width={16} />;
+}
+
+export function renderToolchainProbe() {
+  const reactMarkup = renderToStaticMarkup(<ToolchainProbe />);
+  const fabricSvg = new Rect({
+    fill: "#111111",
+    height: 16,
+    width: 16,
+  }).toSVG();
+
+  return {
+    fabricSvg,
+    fabricVersion,
+    reactMarkup,
+  };
+}