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>

templates/frontend/login-page.php

@@ -0,0 +1,37 @@
+<?php
+declare(strict_types=1);
+
+if (! defined('ABSPATH')) {
+    exit;
+}
+
+/** @var string $error */
+/** @var string $redirect */
+?>
+<div class="us-login-form">
+    <?php if ($error !== '') : ?>
+        <p class="us-error" role="alert"><?php echo esc_html($error); ?></p>
+    <?php endif; ?>
+
+    <form method="post" action="">
+        <?php wp_nonce_field('us_student_login'); ?>
+
+        <p>
+            <label for="log"><?php esc_html_e('Username', 'unsupervised-schedular'); ?></label>
+            <input type="text" name="log" id="log" autocomplete="username" required>
+        </p>
+        <p>
+            <label for="pwd"><?php esc_html_e('Password', 'unsupervised-schedular'); ?></label>
+            <input type="password" name="pwd" id="pwd" autocomplete="current-password" required>
+        </p>
+        <p>
+            <label>
+                <input type="checkbox" name="rememberme">
+                <?php esc_html_e('Remember me', 'unsupervised-schedular'); ?>
+            </label>
+        </p>
+        <p>
+            <input type="submit" name="us_login" value="<?php esc_attr_e('Log In', 'unsupervised-schedular'); ?>">
+        </p>
+    </form>
+</div>