Add Microsoft Clarity tracking

frontend/app/layout.tsx

@@ -1,6 +1,7 @@
 import type { Metadata } from "next";
 import { Inter, JetBrains_Mono } from "next/font/google";
 import { RegisterSW } from "@/components/dashboard/RegisterSW";
+import { MicrosoftClarity } from "@/components/observability/MicrosoftClarity";
 import "./globals.css";
 
 const inter = Inter({
@@ -89,6 +90,7 @@ export default function RootLayout({
         </a>
         <main id="main-content">{children}</main>
         <RegisterSW />
+        <MicrosoftClarity />
       </body>
     </html>
   );

frontend/components/observability/MicrosoftClarity.tsx

@@ -0,0 +1,23 @@
+import Script from "next/script";
+
+const MICROSOFT_CLARITY_PROJECT_ID = "xbydcq2lu2";
+
+const MICROSOFT_CLARITY_SCRIPT = `
+  (function(c,l,a,r,i,t,y){
+      c[a]=c[a]||function(){(c[a].q=c[a].q||[]).push(arguments)};
+      t=l.createElement(r);t.async=1;t.src="https://www.clarity.ms/tag/"+i;
+      y=l.getElementsByTagName(r)[0];y.parentNode.insertBefore(t,y);
+  })(window, document, "clarity", "script", "${MICROSOFT_CLARITY_PROJECT_ID}");
+`;
+
+export function MicrosoftClarity() {
+  if (process.env.NODE_ENV !== "production") {
+    return null;
+  }
+
+  return (
+    <Script id="microsoft-clarity" strategy="afterInteractive">
+      {MICROSOFT_CLARITY_SCRIPT}
+    </Script>
+  );
+}

frontend/components/observability/__tests__/microsoftClarity.test.ts

@@ -0,0 +1,34 @@
+import fs from "node:fs";
+import path from "node:path";
+
+function assert(condition: unknown, message: string) {
+  if (!condition) throw new Error(message);
+}
+
+export function runTests() {
+  const projectRoot = process.cwd();
+  const componentPath = path.join(projectRoot, "components", "observability", "MicrosoftClarity.tsx");
+  const layoutPath = path.join(projectRoot, "app", "layout.tsx");
+
+  assert(fs.existsSync(componentPath), "Microsoft Clarity component must exist");
+
+  const component = fs.readFileSync(componentPath, "utf8");
+  const layout = fs.readFileSync(layoutPath, "utf8");
+
+  assert(
+    component.includes('import Script from "next/script"') &&
+      component.includes('strategy="afterInteractive"'),
+    "Microsoft Clarity must use next/script and load after hydration",
+  );
+  assert(
+    component.includes("xbydcq2lu2") &&
+      component.includes("https://www.clarity.ms/tag/") &&
+      component.includes('window, document, "clarity", "script"'),
+    "Microsoft Clarity must use the configured PolyWeather project script",
+  );
+  assert(
+    layout.includes("@/components/observability/MicrosoftClarity") &&
+      layout.includes("<MicrosoftClarity />"),
+    "root layout must render Microsoft Clarity globally",
+  );
+}