chore: add composer + phpunit dev scaffolding

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/bootstrap.php

@@ -0,0 +1,34 @@
+<?php
+declare(strict_types=1);
+
+// Simple autoloader that mirrors the runtime plugin autoloader,
+// mapping Cf7stg\ClassName → includes/class-class-name.php
+spl_autoload_register(static function (string $class): void {
+    if (strpos($class, 'Cf7stg\\') !== 0) {
+        return;
+    }
+    $relative = substr($class, strlen('Cf7stg\\'));
+    // Turn "PhoneParser" into "phone-parser"
+    $slug = strtolower(preg_replace('/([a-z0-9])([A-Z])/', '$1-$2', $relative));
+    $path = __DIR__ . '/../includes/class-' . $slug . '.php';
+    if (is_file($path)) {
+        require_once $path;
+    }
+});
+
+// Minimal shims for functions used by pure-logic classes when WP is absent.
+if (!function_exists('apply_filters')) {
+    function apply_filters($tag, $value) { return $value; }
+}
+if (!function_exists('esc_html')) {
+    function esc_html($s) { return htmlspecialchars((string)$s, ENT_QUOTES, 'UTF-8'); }
+}
+if (!function_exists('esc_url')) {
+    function esc_url($s) { return filter_var((string)$s, FILTER_SANITIZE_URL); }
+}
+if (!function_exists('wp_strip_all_tags')) {
+    function wp_strip_all_tags($s) { return trim(strip_tags((string)$s)); }
+}
+if (!function_exists('__')) {
+    function __($text) { return $text; }
+}