Everything that differs between specialties as data is already stored as data.
What is left is behaviour — when a case opens, what happens once a session ends —
so it becomes a TreatmentWorkflow resolved through a tagged-service registry.
The booking path calls one collaborator and never names a specialty; adding
dentistry is a new class, not an edit to confirmation.
A clinic that has chosen no practice domain still gets working multi-session
courses: DefaultTreatmentWorkflow answers for null and for any code without a
dedicated implementation, keeping "unset means behave as today, not error".
LaserTreatmentWorkflow is deliberately empty beyond claiming `beauty` — it is the
seam where laser-specific behaviour will land without disturbing anyone else.
Session due dates are anchored to the previous session's actual finish, so a
patient who comes twenty days late shifts the rest of their course instead of
getting the next session while it can still do nothing. Only the next session is
recomputed; later ones keep their estimate because they are anchored to nothing
yet.
Attachment targets the first session without an appointment rather than the
first open one: a patient booking again mid-course was otherwise matched to the
session that already had a booking, and the second appointment went nowhere.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
