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/vitest.config.ts

@@ -10,6 +10,7 @@ export default defineConfig({
       "@fusion/core": fileURLToPath(new URL("../../packages/core/src/index.ts", import.meta.url)),
       "@fusion/plugin-sdk": fileURLToPath(new URL("../../packages/plugin-sdk/src/index.ts", import.meta.url)),
       "@fusion/dashboard": fileURLToPath(new URL("../../packages/dashboard", import.meta.url)),
+      "lucide-react": fileURLToPath(new URL("../../packages/dashboard/node_modules/lucide-react", import.meta.url)),
     },
   },
   test: {