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

src/Schema.php

@@ -40,6 +40,7 @@ class Schema {
                 status        VARCHAR(20)     NOT NULL DEFAULT 'pending',
                 payment_id    BIGINT UNSIGNED DEFAULT NULL,
                 notes         TEXT,
+                booked_by     BIGINT UNSIGNED NOT NULL DEFAULT 0,
                 created_at    DATETIME        NOT NULL,
                 PRIMARY KEY (id),
                 KEY slot_id (slot_id),
@@ -104,6 +105,9 @@ class Schema {
                 registration_id   BIGINT UNSIGNED NOT NULL,
                 student_id        BIGINT UNSIGNED NOT NULL,
                 answer_value      TEXT,
+                collected_via     VARCHAR(20)     DEFAULT NULL,
+                collected_note    VARCHAR(191)    DEFAULT NULL,
+                recorded_by       BIGINT UNSIGNED NOT NULL DEFAULT 0,
                 created_at        DATETIME        NOT NULL,
                 PRIMARY KEY (id),
                 KEY question_id (question_id),
@@ -145,6 +149,9 @@ class Schema {
                 registration_id   BIGINT UNSIGNED NOT NULL,
                 accepted_at       DATETIME        NOT NULL,
                 ip_address        VARCHAR(45)     DEFAULT NULL,
+                collected_via     VARCHAR(20)     DEFAULT NULL,
+                collected_note    VARCHAR(191)    DEFAULT NULL,
+                recorded_by       BIGINT UNSIGNED NOT NULL DEFAULT 0,
                 PRIMARY KEY (id),
                 KEY policy_version_id (policy_version_id),
                 KEY student_id (student_id),
@@ -210,6 +217,7 @@ class Schema {
                 instructor_id BIGINT UNSIGNED NOT NULL,
                 status        VARCHAR(20)     NOT NULL DEFAULT 'active',
                 payment_id    BIGINT UNSIGNED DEFAULT NULL,
+                enrolled_by   BIGINT UNSIGNED NOT NULL DEFAULT 0,
                 enrolled_at   DATETIME        NOT NULL,
                 PRIMARY KEY (id),
                 KEY offering_id (offering_id),