feat(docs): add laser treatment plan and related ADRs for multi-session treatments

CONTEXT.md

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+# ClinicPro Backend
+
+The Symfony API and bundled React admin that owns all clinic data, scheduling and auth for the
+ClinicPro product. This glossary records the language the backend uses for its own concepts.
+
+## Language
+
+### Clinic configuration
+
+**Practice Domain**:
+The single field of practice a clinic declares it operates in — beauty, dental, orthopaedics. It is a
+configuration key: it selects which dashboard, forms and treatment workflows the clinic gets. A
+clinic has exactly one.
+_Avoid_: Specialty, clinic type, field, discipline
+
+**Specialty**:
+A medical specialty label attached to a Clinic or a Doctor, used by the public booking site for
+listing and SEO. It is descriptive, not configuration — it never selects behaviour.
+_Avoid_: Practice Domain, category
+
+### Treatment
+
+**Treatment Protocol**:
+The template attached to a service that says a course of that service runs over several sessions, when
+each one falls due, which doctor supervises the course, and which staff are allowed to perform it.
+Defined once by the clinic manager, not per patient.
+_Avoid_: Treatment plan, course template, session config
+
+**Supervising Doctor**:
+The doctor answerable for a Treatment Protocol and for every Treatment Case opened from it. They carry
+clinical responsibility; they do not necessarily perform the treatment.
+_Avoid_: Doctor, owner, responsible
+
+**Operator**:
+The staff member who actually performs a Treatment Session — runs the device, treats each area, and
+records what was done. Chosen at booking time from the staff the Treatment Protocol allows.
+_Avoid_: Technician, performer, staff, nurse
+
+**Treatment Case**:
+One patient's run of a Treatment Protocol, from the first booking until the course ends. It owns the
+sessions and carries the state of the whole course.
+_Avoid_: Treatment plan, patient file, dossier, episode
+
+**Treatment Session**:
+One numbered step of a Treatment Case — session 3 of 8. It exists whether or not it has been booked
+yet, so its number survives cancellation and rescheduling. It holds the plan and the clinical record,
+never money.
+_Avoid_: Appointment, visit, session slot, patient session
+
+**Visit Record**:
+The billing side of one attended visit — services rendered, insurance shares, discounts, payments. It
+comes into existence when an Appointment is confirmed, so a Treatment Session that has not been booked
+yet has none.
+_Avoid_: Session, invoice, patient session
+
+**Appointment**:
+A reserved slot in a calendar. It is the booking, not the treatment. A Treatment Session may point at
+one, at a different one after rescheduling, or at none while still unbooked.
+_Avoid_: Session, booking, reservation
+
+**Treatment Area**:
+A region of the body a Treatment Session is performed on — underarms, bikini line. A single session
+covers several, each completed and recorded on its own.
+_Avoid_: Zone, body part, region
+
+**Session Area Record**:
+What the operator actually did to one Treatment Area in one Treatment Session — the device used, the
+parameters it was set to, how long it took, and any note.
+_Avoid_: Treatment log, area result, shot record