Notes lifecycle

POST /api/therapy/notes/{note_id}/transition       # workflow state transition
POST /api/therapy/notes/{note_id}/approve          # provider signature
POST /api/therapy/notes/{note_id}/finalize         # finalize after approvals
POST /api/therapy/notes/{note_id}/track-change     # track section edits

POST /api/therapy/validate-note

POST /api/therapy/suggest-codes