feat: implement pipeline feature for automated workflow steps

- Introduced a new pipeline service to manage custom workflow steps that execute after a feature is marked "In Progress".
- Added API endpoints for configuring, saving, adding, updating, deleting, and reordering pipeline steps.
- Enhanced the UI to support pipeline settings, including a dialog for managing steps and integration with the Kanban board.
- Updated the application state management to handle pipeline configurations per project.
- Implemented dynamic column generation in the Kanban board to display pipeline steps between "In Progress" and "Waiting Approval".
- Added documentation for the new pipeline feature, including usage instructions and configuration details.

This feature allows for a more structured workflow, enabling automated processes such as code reviews and testing after feature implementation.

apps/ui/src/components/views/graph-view/components/task-node.tsx

@@ -76,7 +76,10 @@ const priorityConfig = {
 };
 
 export const TaskNode = memo(function TaskNode({ data, selected }: TaskNodeProps) {
-  const config = statusConfig[data.status] || statusConfig.backlog;
+  // Handle pipeline statuses by treating them like in_progress
+  const status = data.status || 'backlog';
+  const statusKey = status.startsWith('pipeline_') ? 'in_progress' : status;
+  const config = statusConfig[statusKey as keyof typeof statusConfig] || statusConfig.backlog;
   const StatusIcon = config.icon;
   const priorityConf = data.priority ? priorityConfig[data.priority as 1 | 2 | 3] : null;