feat(FN-3084): add active node visual states to dependency graph

The merge adds active graph node visual states (highlight, pulsing indicator, selected border) to the dependency-graph plugin with corresponding test coverage, introduces a plugin AI security scan gate and GraphTaskNode wrapper per FN-3426, and includes a small test stabilization fix alongside docum

Fusion-Task-Id: FN-3084

plugins/fusion-plugin-dependency-graph/src/dashboard-interop.d.ts

@@ -1,3 +1,9 @@
+declare module "@fusion/dashboard/app/utils/taskStuck" {
+  import type { Task } from "@fusion/core";
+
+  export function isTaskStuck(task: Task, taskStuckTimeoutMs?: number, lastFetchTimeMs?: number): boolean;
+}
+
 declare module "@fusion/dashboard/app/components/TaskCard" {
   import type { Column, Task, TaskDetail } from "@fusion/core";
   import type { ReactElement } from "react";