feat: Add media upload support for issue descriptions

[Hinne1]

Problem

Currently there's no way to upload and embed images in issue descriptions via the CLI. The !media[id] syntax requires knowing the media ID, which is only available after uploading via Jira's media service.

Proposed Solution

Add support for embedding local images in descriptions:

# Upload and embed an image
atl issue edit PROJ-1234 --description "See screenshot below:" --attach-image ./screenshot.png

# Or inline syntax in Markdown
atl issue edit PROJ-1234 --description "See screenshot: ![](./screenshot.png)"

Implementation Notes

1. Implement Jira media upload API integration
2. Upload image to media service, get back collection/ID
3. Convert to proper ADF mediaSingle node
4. Insert at appropriate position in description

API Reference

• Media upload: POST /rest/api/3/issue/{issueIdOrKey}/attachments or Jira media service
• Need to handle the media token/collection workflow

Related

• feat: Preserve embedded media when editing descriptions #14 - Preserve embedded media when editing descriptions
• feat: Add --append flag for issue description editing #12 - Add --append flag for descriptions