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

tests/Unit/Policy/AcceptanceRepositoryTest.php

@@ -38,9 +38,13 @@ class AcceptanceRepositoryTest extends TestCase
                         && $d['registration_id'] === 12
                         // No explicit acceptor: the student agreed for themselves.
                         && $d['accepted_by'] === 5
-                        && $d['ip_address'] === '203.0.113.7';
+                        && $d['ip_address'] === '203.0.113.7'
+                        // Ticked online: no collection provenance to record.
+                        && null === $d['collected_via']
+                        && null === $d['collected_note']
+                        && 0 === $d['recorded_by'];
                 }),
-                ['%d', '%d', '%d', '%s', '%d', '%s', '%s']
+                ['%d', '%d', '%d', '%s', '%d', '%s', '%s', '%s', '%d', '%s']
             );
         $this->db->insert_id = 1;