Image attachments in comments and replies

Add image attachments to Screenote comments and answers. Users should be able to upload one or more screenshots or other images while writing any task comment or answering a brainstorm/question prompt, so design references can be attached directly to the relevant message. Show upload progress and previews, allow removal before submission, persist and render attachments inline with the comment or answer, provide click-to-view/full-size behavior, and enforce sensible supported formats, size/count limits, validation, authorization, and secure storage. Ensure attachments remain associated with the correct task, comment, answer, and author, and cover both light and dark UI states plus relevant tests.