refactor(tui): move shared components (help bar, issue list, modals, etc.) into components folder. Also added kanban board view.

pkg/tui/msgs/msgs.go

@@ -3,5 +3,5 @@ package msgs
 // SwitchToDashboardMsg signals to switch to the main dashboard view.
 type SwitchToDashboardMsg struct{}
 
-// SwitchToDashboard2Msg signals to switch to the dashboard2 view.
-type SwitchToDashboard2Msg struct{}
+// SwitchToKanbanBoardMsg signals to switch to the kanban board view.
+type SwitchToKanbanBoardMsg struct{}