feat: update kanban view, dashboard view, add backlog status

src/kanban/outboundMessages.ts

@@ -1,6 +1,15 @@
 import { AppError } from "@/error";
+import { TaskScope } from "@/model/taskLocation";
 import { KanbanBoard } from "./buildKanbanBoard";
+import { KanbanScopeFilter } from "./messages";
 
 /** Host → webview. */
 export type KanbanOutboundMessage =
-	{ type: "state"; board: KanbanBoard } | { type: "error"; error: AppError };
+	| {
+			variant: "state";
+			board: KanbanBoard;
+			scopeFilter: KanbanScopeFilter;
+			showHidden: boolean;
+			availableScopes: TaskScope[];
+	  }
+	| { variant: "error"; error: AppError };