Bulk delete availability slots from the admin list view

The list view of Current Slots gets a checkbox per unbooked slot, a
select-all header checkbox, and a Delete selected button submitting a
new bulk_delete form action. Each id is ownership-checked through the
same path as single delete; the repository's is_booked guard refuses
booked slots as a second layer. Row checkboxes attach to the bulk form
via the HTML form attribute because the table already contains the
per-row delete forms and forms cannot nest.

Closes #57

Co-Authored-By: Claude Fable 5 <[email protected]>

templates/admin/availability.php

@@ -136,9 +136,22 @@ $deleteForm = static function (\Unsupervised\Schedular\Availability\Availability
     <?php elseif (empty($slots)) : ?>
         <p><?php esc_html_e('No availability slots configured.', 'unsupervised-schedular'); ?></p>
     <?php else : ?>
+        <?php
+        // Bulk-delete form. The row checkboxes live inside the table and are
+        // associated via the HTML form attribute, because the table also
+        // contains the per-row delete forms and forms cannot nest.
+        ?>
+        <form method="post" id="usc-bulk-delete-form" onsubmit="return confirm('<?php echo esc_js(__('Delete the selected slots?', 'unsupervised-schedular')); ?>');">
+            <?php wp_nonce_field('usc_availability_action'); ?>
+            <input type="hidden" name="usc_action" value="bulk_delete">
+        </form>
         <table class="wp-list-table widefat fixed striped">
             <thead>
                 <tr>
+                    <td class="manage-column column-cb check-column">
+                        <input type="checkbox" id="cb-select-all-1">
+                        <label for="cb-select-all-1"><span class="screen-reader-text"><?php esc_html_e('Select all', 'unsupervised-schedular'); ?></span></label>
+                    </td>
                     <th><?php esc_html_e('Start', 'unsupervised-schedular'); ?></th>
                     <th><?php esc_html_e('End', 'unsupervised-schedular'); ?></th>
                     <th><?php esc_html_e('Length', 'unsupervised-schedular'); ?></th>
@@ -149,6 +162,11 @@ $deleteForm = static function (\Unsupervised\Schedular\Availability\Availability
             <tbody>
                 <?php foreach ($slots as $slot) : ?>
                     <tr>
+                        <th scope="row" class="check-column">
+                            <?php if (! $slot->isBooked) : ?>
+                                <input type="checkbox" name="slot_ids[]" form="usc-bulk-delete-form" value="<?php echo esc_attr((string) $slot->id); ?>">
+                            <?php endif; ?>
+                        </th>
                         <td><?php echo esc_html((string) mysql2date('M j, Y g:i A', $slot->startDt)); ?></td>
                         <td><?php echo esc_html((string) mysql2date('M j, Y g:i A', $slot->endDt)); ?></td>
                         <td><?php echo esc_html((string) $slot->durationMinutes . ' min'); ?></td>
@@ -162,5 +180,10 @@ $deleteForm = static function (\Unsupervised\Schedular\Availability\Availability
                 <?php endforeach; ?>
             </tbody>
         </table>
+        <p>
+            <button type="submit" class="button" form="usc-bulk-delete-form">
+                <?php esc_html_e('Delete selected', 'unsupervised-schedular'); ?>
+            </button>
+        </p>
     <?php endif; ?>
 </div>