perf(cli): enable the Node.js compile cache (#17782)

Author: Princesseuh

.changeset/tidy-pears-shake.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Improves the performance of the Astro CLI in local by enabling Node's module compilation cache.

packages/astro/bin/astro.mjs

@@ -1,6 +1,21 @@
 #!/usr/bin/env node
 'use strict';
 
+import module from 'node:module';
+
+// In CI writing the cache is (most of the time) harmful, as it'll never get re-used and just slows down the CLI.
+if (!process.env.CI) {
+	try {
+		module.enableCompileCache?.();
+		// Long-running commands like `astro dev` never reach the flush that happens on process exit.
+		setTimeout(() => {
+			try {
+				module.flushCompileCache?.();
+			} catch {}
+		}, 10_000).unref();
+	} catch {}
+}
+
 const CI_INSTRUCTIONS = {
 	NETLIFY: 'https://docs.netlify.com/configure-builds/manage-dependencies/#node-js-and-javascript',
 	GITHUB_ACTIONS: