feat: fix workout taxonomy to 7 types, add pace/HR-zone fields to the API

backend/internal/api/server.go

@@ -65,10 +65,8 @@ func (s *Server) Router() http.Handler {
 
 		r.Route("/workout-kinds", func(r chi.Router) {
 			r.Get("/", s.handleListWorkoutKinds)
-			r.Post("/", s.handleCreateWorkoutKind)
 			r.Get("/{id}", s.handleGetWorkoutKind)
 			r.Put("/{id}", s.handleUpdateWorkoutKind)
-			r.Delete("/{id}", s.handleDeleteWorkoutKind)
 			r.Post("/{id}/reclassify", s.handleReclassifyKind)
 		})