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/Booking/LessonTest.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 namespace Unsupervised\Schedular\Tests\Unit\Booking;
 
 use Unsupervised\Schedular\Booking\Lesson;
+use Unsupervised\Schedular\Registration\Answer;
 use Unsupervised\Schedular\Tests\Unit\TestCase;
 
 class LessonTest extends TestCase
@@ -76,4 +77,21 @@ class LessonTest extends TestCase
             self::assertArrayHasKey($key, $arr);
         }
     }
+
+    public function testAWeeklySeriesSharesOneIntakeRegistration(): void
+    {
+        // Occurrence 12 of a series anchored on lesson 7: answered for once.
+        $occurrence = new Lesson(slotId: 10, studentId: 5, instructorId: 3, offeringId: 8, seriesId: 7, id: 12);
+
+        self::assertSame(Answer::REG_LESSON, $occurrence->intakeRegistrationType());
+        self::assertSame(7, $occurrence->intakeRegistrationId());
+        // A single lesson is its own registration.
+        self::assertSame(12, (new Lesson(slotId: 10, studentId: 5, instructorId: 3, id: 12))->intakeRegistrationId());
+    }
+
+    public function testOnlyAStudioBookedLessonIsStaffRegistered(): void
+    {
+        self::assertFalse((new Lesson(slotId: 10, studentId: 5, instructorId: 3, id: 12))->isStaffRegistered());
+        self::assertTrue((new Lesson(slotId: 10, studentId: 5, instructorId: 3, bookedBy: 9, id: 12))->isStaffRegistered());
+    }
 }