[Feature request] New utility components for section titles and subtitles

### Description

Add utility components for section titles and subtitles. These would help organize and label groups of annotations on the canvas, making large annotation files easier to navigate and understand.

Start by reviewing the existing components in the Figma asset library to understand how annotation elements are organized. Clarify the intended appearance, behavior, and placement of section title and subtitle components; done means both utility components are defined and fit the toolkit’s existing patterns.

Written by the indexing model from the issue text.