Fix workflow step execution wiring

packages/engine/src/merger.ts

@@ -1539,6 +1539,7 @@ async function executePostMergePromptStep(
   rootDir: string,
   settings: Settings,
 ): Promise<{ success: boolean; output?: string; error?: string }> {
+  const toolMode: "coding" | "readonly" = workflowStep.toolMode || "readonly";
   const systemPrompt = `You are a post-merge workflow step agent executing: ${workflowStep.name}
 
 Task Context:
@@ -1567,7 +1568,7 @@ If issues are found that need attention, describe them clearly.`;
     const { session } = await createKbAgent({
       cwd: rootDir,
       systemPrompt,
-      tools: "readonly",
+      tools: toolMode,
       defaultProvider: stepProvider,
       defaultModelId: stepModelId,
       fallbackProvider: settings.fallbackProvider,