fix: Task tool subagent spawn and isolated block labels (#561)

Co-authored-by: Letta <noreply@letta.com>

src/agent/subagents/builtin/recall.md

@@ -3,7 +3,7 @@ name: recall
 description: Search conversation history to recall past discussions, decisions, and context
 tools: Skill, Bash, Read, BashOutput
 model: haiku
-memoryBlocks: human, persona
+memoryBlocks: human, persona, skills, loaded_skills
 mode: stateless
 ---
 

src/agent/subagents/manager.ts

@@ -308,7 +308,7 @@ function buildSubagentArgs(
   userPrompt: string,
 ): string[] {
   const args: string[] = [
-    "--new",
+    "--new-agent",
     "--system",
     type,
     "--model",