feat(functions): add Composer autoloader phpdoc

Author: rsanchez-beapi

functions.php

@@ -1,5 +1,13 @@
 <?php
 
+/**
+ * Bootstrap the theme Composer autoloader when classes are not already available.
+ *
+ * Root projects (Bedrock, composer-scaffold-theme) usually register this namespace
+ * via their own autoload. Standalone setups (wp-env, theme-only) rely on vendor/.
+ *
+ * @since 5.4.0
+ */
 if ( ! class_exists( 'BEA\\Theme\\Framework\\Framework', false ) ) {
 	$autoloader = __DIR__ . '/vendor/autoload.php';