feat(catalog): class template editing

Templates were delete-and-recreate only. Adds PUT
/v1/catalog/class-templates/{id} across repository, service (sharing
the create-time validation), route, spec, and client; the classes tab
gets a pencil action that loads the row into the form with a
save/cancel affordance.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

apps/backend/internal/db/classes.go

@@ -71,6 +71,24 @@ func (r *PGRepository) CreateClassTemplate(ctx context.Context, params CreateCla
 	return record, err
 }
 
+func (r *PGRepository) UpdateClassTemplate(ctx context.Context, templateID string, params CreateClassTemplateParams) (ClassTemplateRecord, error) {
+	var record ClassTemplateRecord
+	err := r.pool.QueryRow(ctx, `
+		UPDATE class_templates
+		SET title = $2, duration_minutes = $3, capacity = $4
+		WHERE id = $1
+		RETURNING `+classTemplateColumns+`
+	`, templateID, params.Title, params.DurationMinutes, params.Capacity).Scan(
+		&record.ID,
+		&record.TenantID,
+		&record.Title,
+		&record.DurationMinutes,
+		&record.Capacity,
+		&record.CreatedAt,
+	)
+	return record, err
+}
+
 func (r *PGRepository) DeleteClassTemplate(ctx context.Context, templateID string) error {
 	_, err := r.pool.Exec(ctx, `DELETE FROM class_templates WHERE id = $1`, templateID)
 	return err

apps/backend/internal/db/repository.go

@@ -32,6 +32,7 @@ type Repository interface {
 	ListClassTemplatesByTenant(ctx context.Context, tenantID string) ([]ClassTemplateRecord, error)
 	GetClassTemplateByID(ctx context.Context, templateID string) (ClassTemplateRecord, error)
 	CreateClassTemplate(ctx context.Context, params CreateClassTemplateParams) (ClassTemplateRecord, error)
+	UpdateClassTemplate(ctx context.Context, templateID string, params CreateClassTemplateParams) (ClassTemplateRecord, error)
 	DeleteClassTemplate(ctx context.Context, templateID string) error
 	ListBookingsByTenantBetween(ctx context.Context, tenantID string, from time.Time, to time.Time) ([]BookingRecord, error)
 	CreateBooking(ctx context.Context, params CreateBookingParams) (CreatedBooking, error)
@@ -1311,6 +1312,18 @@ func (r *MemoryRepository) CreateClassTemplate(_ context.Context, params CreateC
 	return record, nil
 }
 
+func (r *MemoryRepository) UpdateClassTemplate(_ context.Context, templateID string, params CreateClassTemplateParams) (ClassTemplateRecord, error) {
+	for index := range r.classTemplates {
+		if r.classTemplates[index].ID == templateID {
+			r.classTemplates[index].Title = params.Title
+			r.classTemplates[index].DurationMinutes = params.DurationMinutes
+			r.classTemplates[index].Capacity = params.Capacity
+			return r.classTemplates[index], nil
+		}
+	}
+	return ClassTemplateRecord{}, pgx.ErrNoRows
+}
+
 func (r *MemoryRepository) DeleteClassTemplate(_ context.Context, templateID string) error {
 	for i, template := range r.classTemplates {
 		if template.ID == templateID {