feat: Sprint 2 — WordPress plugin (auth/api/site-info/admin) + web SiteConnector

- plugin: Wursor_Auth (token hashing, HMAC, scoped tokens), Wursor_API (REST + auth), Wursor_Site_Info (builder/capabilities/preflight), Wursor_Admin
- plugin: test-auth.php (10 auth tests, run in a WP+PHP env)
- web: SiteConnector pairing UI (code + poll + states)
- api: PluginClient signs full REST route (matches WP get_route)
- 92 unit tests green

plugin/wursor.php

@@ -0,0 +1,19 @@
+<?php
+/**
+ * Plugin Name: Wursor
+ * Description: Connects this WordPress site to Wursor for safe, previewed changes.
+ * Version: 0.1.0
+ * Requires PHP: 7.4
+ * Author: Wursor
+ * License: GPL-2.0-or-later
+ */
+
+defined('ABSPATH') || exit;
+
+require_once __DIR__ . '/src/class-auth.php';
+require_once __DIR__ . '/src/class-site-info.php';
+require_once __DIR__ . '/src/class-api.php';
+require_once __DIR__ . '/src/class-admin.php';
+
+add_action('rest_api_init', array('Wursor_API', 'register_routes'));
+add_action('admin_menu', array('Wursor_Admin', 'register_menu'));