Added

• Structured metadata field on task comments (Record<string, unknown>) for machine-readable progress tracking. Supported on add_task_comment MCP tool, batch_update_tasks inline comments, and REST API endpoints. Predefined keys: action, commit, branch, files_changed, next_step.
• Frontend renders comment metadata as tags below comment body in task sidenav.

Fixed

• updateComment parser method and PUT /tasks/:id/comments/:commentId now accept and persist metadata updates.
• Frontend API client addComment and updateComment forward metadata.