Initial plugin scaffold: lesson scheduling WordPress plugin

- Custom DB tables for availability slots and lesson bookings
- Instructor (wp-admin) and student (front-end) roles with custom capabilities
- REST API under us-scheduler/v1 for availability CRUD and booking
- [us_booking] and [us_student_login] shortcodes for student front end
- PHPUnit + Brain\Monkey unit test suite (29 tests)
- Gitea Actions CI: lint, PHPStan, tests on PHP 8.1/8.2/8.3, no-debug check
- Feature docs under docs/features/

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/bootstrap.php

@@ -0,0 +1,15 @@
+<?php
+declare(strict_types=1);
+
+require_once dirname(__DIR__) . '/vendor/autoload.php';
+
+// Minimal WordPress constants required by plugin code under test.
+if (! defined('ABSPATH')) {
+    define('ABSPATH', sys_get_temp_dir() . '/wordpress/');
+}
+
+define('WPINC', 'wp-includes');
+define('USC_VERSION', '1.0.0');
+define('USC_PLUGIN_FILE', dirname(__DIR__) . '/unsupervised-schedular.php');
+define('USC_PLUGIN_DIR', dirname(__DIR__) . '/');
+define('USC_PLUGIN_URL', 'http://example.com/wp-content/plugins/unsupervised-schedular/');