- Add updateSubtaskStatus method in TaskService to handle subtask IDs like '21.1' - Parse parent task ID and subtask ID from dotted notation - Find and update specific subtask within parent task structure - Save updated parent task back to storage (works with both file and API storage) - Fix regression introduced in v0.27.0 where subtask updates were blocked - Resolves issue #1247 🤖 Generated with [Claude Code](https://claude.ai/code) Co-authored-by: Ralph Khreish <Crunchyman-ralph@users.noreply.github.com>