feat(FN-3490): add workflow step execution for plugins

This merge adds WorkflowStepManager UI enhancements, extends the plugin-runner with new execution capabilities, expands executor tests with improved restart and mock handling, and adds agent routes for the dashboard. The changes span core plugin loading, dashboard components, and engine execution lo

Fusion-Task-Id: FN-3490

packages/core/src/store.ts

@@ -6043,7 +6043,7 @@ ${stepsSection}`;
       phase: "pre-merge",
       prompt: entry.template.prompt,
       toolMode: entry.template.toolMode,
-      enabled: true,
+      enabled: entry.template.enabled ?? true,
       createdAt: now,
       updatedAt: now,
     };