fix: fall back to package.json for CLI version detection (#21382)

## Summary

Fixes `aztec --version` returning `unknown` when installed via `install.aztec-labs.com`.

Closes https://linear.app/aztec-labs/issue/A-642/aztec-version-returns-unkonwn

ClaudeBox log: https://claudebox.work/s/9b17d34db367f45c?run=1

Author: AztecBot

yarn-project/stdlib/src/update-checker/package_version.ts

@@ -3,15 +3,28 @@ import { fileURLToPath } from '@aztec/foundation/url';
 import { readFileSync } from 'fs';
 import { dirname, resolve } from 'path';
 
-/** Returns the package version from the release-please manifest, or undefined if not found. */
+/** Returns the package version from the release-please manifest or the package.json, or undefined if not found. */
 export function getPackageVersion(): string | undefined {
+  const dir = dirname(fileURLToPath(import.meta.url));
+
+  // Try the release-please manifest first (works in dev/repo checkout).
   try {
-    const releasePleaseManifestPath = resolve(
-      dirname(fileURLToPath(import.meta.url)),
-      '../../../../.release-please-manifest.json',
-    );
+    const releasePleaseManifestPath = resolve(dir, '../../../../.release-please-manifest.json');
     return JSON.parse(readFileSync(releasePleaseManifestPath).toString())['.'];
   } catch {
-    return undefined;
+    // Not in a repo checkout, fall through.
+  }
+
+  // Fall back to the stdlib package.json version (works in npm-installed packages).
+  try {
+    const packageJsonPath = resolve(dir, '../../package.json');
+    const version = JSON.parse(readFileSync(packageJsonPath).toString()).version;
+    if (version && version !== '0.1.0') {
+      return version;
+    }
+  } catch {
+    // No package.json found either.
   }
+
+  return undefined;
 }