Let the studio book lessons and record intake collected elsewhere

Two related gaps, closed together because the second is created by the first.

A private lesson could only be booked by the student or their guardian, so a
booking taken over the phone had no way in — where group classes have had "Add
students directly" all along. "Book a lesson for a student" is now a panel on
Scheduler and My Lessons: student, open time, lesson type, with weekly term
reservations and a no-charge option for make-up lessons. The booking core is
extracted to Booking\LessonBooker and shared with POST /bookings, so the two
paths cannot drift on offering rules, slot claiming, or billing.

That leaves a registration with no intake answers and no policy acceptances,
because nobody was at a keyboard to give them — already true of every directly
added group-class student. Ticking the boxes on a student's behalf would be an
audit trail that says something untrue, so instead the answers are collected
another way and recorded afterwards, from a lesson's or an enrolment's detail
page. Every recording must say how it was collected, which is stamped on each
row along with who typed it and shown in a new "How it was given" column: a
policy ticked online and one transcribed from paper must never look alike.

Only staff-made registrations qualify (us_lessons.booked_by,
us_group_enrollments.enrolled_by) — one the student made already holds their
own answers. Only what is still missing can be recorded, re-checked at write
time, so a stale or double-posted form cannot duplicate or overwrite. No IP is
stored for a transcription, and accepted_by stays the student while recorded_by
names the staff member.

Intake is now generic over Registration\IntakeSubject, which Lesson and
Enrollment both implement; LessonDetail became Registration\IntakeAudit and is
shared by both detail views rather than duplicated.

Closes #182

Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01QfHt6CyJHz6KkA4RuaS7WK

templates/admin/my-group-class-detail.php

@@ -6,7 +6,7 @@ if (! defined('ABSPATH')) {
 }
 
 /**
- * @var array{id: int|null, title: string, when: string, capacity: int|null, enrolled: int, invite_only: bool, instructor: string, price: float, currency: string, duration: int|null, description: string|null, schedule_note: string|null, deadline: string, enrollment_open: bool, active: bool, roster: list<array{student: string, status: string, payment: string|null}>, invited: list<array{who: string, kind: string}>} $class
+ * @var array{id: int|null, title: string, when: string, capacity: int|null, enrolled: int, invite_only: bool, instructor: string, price: float, currency: string, duration: int|null, description: string|null, schedule_note: string|null, deadline: string, enrollment_open: bool, active: bool, roster: list<array{id: int, student: string, status: string, payment: string|null}>, invited: list<array{who: string, kind: string}>} $class
  * @var list<array{id: int, name: string}> $students
  * @var string $notice
  * @var string $baseUrl
@@ -122,6 +122,7 @@ if (! defined('ABSPATH')) {
                     <th><?php esc_html_e('Student', 'unsupervised-schedular'); ?></th>
                     <th><?php esc_html_e('Enrolment', 'unsupervised-schedular'); ?></th>
                     <th><?php esc_html_e('Payment', 'unsupervised-schedular'); ?></th>
+                    <th><?php esc_html_e('Intake', 'unsupervised-schedular'); ?></th>
                 </tr>
             </thead>
             <tbody>
@@ -130,6 +131,9 @@ if (! defined('ABSPATH')) {
                         <td><?php echo esc_html($entry['student']); ?></td>
                         <td><?php echo esc_html($entry['status']); ?></td>
                         <td><?php echo esc_html($entry['payment'] ?? '—'); ?></td>
+                        <td>
+                            <a href="<?php echo esc_url(add_query_arg('enrollment_id', (string) $entry['id'], $baseUrl)); ?>"><?php esc_html_e('View', 'unsupervised-schedular'); ?></a>
+                        </td>
                     </tr>
                 <?php endforeach; ?>
             </tbody>