* feat(views): show sub-issue progress indicator in issue list rows
When an issue has sub-issues, display a circular progress ring with
done/total count (e.g. "2/3") in the list row. Progress is computed
from the already-loaded issue list without additional API calls.
Extracts ProgressRing into a shared component reused by both
issue-detail and list-row.
* feat(views): refine sub-issue progress UI and add to board view
- Move progress badge right after issue title (not pushed to far right)
- Increase progress ring size from 11px to 14px for better visibility
- Add sub-issue progress indicator to board card view
- Thread childProgressMap through BoardView → BoardColumn → BoardCard
