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

docs/features/policies.md

@@ -36,7 +36,10 @@ The studio admin drafts, versions, and publishes policies (e.g. cancellation, pa
 | `registration_type` | VARCHAR(20)      | `lesson` or `enrollment`                              |
 | `registration_id`   | BIGINT UNSIGNED  | FK → `us_lessons.id` or `us_group_enrollments.id`     |
 | `accepted_at`       | DATETIME         | Timestamp of acceptance                              |
-| `ip_address`        | VARCHAR(45)      | IP captured at acceptance (audit trail)              |
+| `ip_address`        | VARCHAR(45)      | IP captured at acceptance (audit trail); NULL when not given online |
+| `collected_via`     | VARCHAR(20)      | How the acceptance reached the studio when it was not given online (`paper` / `in_person` / `phone` / `email` / `other`); NULL means online |
+| `collected_note`    | VARCHAR(191)     | Free-text detail for the above; required for `other` |
+| `recorded_by`       | BIGINT UNSIGNED  | Staff member who typed a collected-elsewhere acceptance in; 0 otherwise |
 
 ## Versioning & Acceptance Rules
 - Editing a published policy creates a new `draft` version; the old version stays `published` until the draft is published.
@@ -91,3 +94,10 @@ cover every policy's current version or the registration is rejected.
 box, where that differs from `student_id` — a guardian agreeing on a child's
 behalf. It defaults to 0, read back as "the student agreed for themselves"
 (`PolicyAcceptance::acceptorOrStudent()`). See `parent-guardian-accounts.md`.
+
+`recorded_by` answers a different question: who *entered* the acceptance, for one
+collected on paper or over the phone and typed in afterwards. The student still
+agreed, so `accepted_by` stays theirs; `collected_via` says how, and no IP is
+stored because they were never at a browser. Only lessons the studio booked can
+be recorded against — see **Recording Intake Collected Elsewhere** in
+`lesson-booking.md`.