feat: add commit hash to environment variables and create HealthPage component to display it

app/health/page.tsx

@@ -0,0 +1,7 @@
+const HealthPage = () => {
+  const commit = process.env.NEXT_PUBLIC_COMMIT_HASH;
+
+  return <div>{commit}</div>;
+};
+
+export default HealthPage;

next.config.mjs

@@ -1,5 +1,7 @@
 import withBundleAnalyzer from '@next/bundle-analyzer';
+import { execSync } from 'child_process';
 
+const commitHash = execSync('git rev-parse --short HEAD').toString().trim();
 const IS_PRODUCTION = process.env.NODE_ENV === 'production';
 const SUPABASE_URL = process.env.NEXT_PUBLIC_SUPABASE_URL;
 const ENABLE_REACT_COMPILER = process.env.ENABLE_REACT_COMPILER === 'true';
@@ -68,6 +70,9 @@ const config = {
   /** We already do linting and typechecking as separate tasks in CI */
   eslint: { ignoreDuringBuilds: true },
   typescript: { ignoreBuildErrors: true },
+  env: {
+    NEXT_PUBLIC_COMMIT_HASH: commitHash,
+  },
 };
 
 export default withBundleAnalyzer({