docs: refine spawn workspace guidance wording

Adjust the spawn tool description to keep the workspace-organizing hint while
avoiding language that sounds like the system automatically assigns a dedicated
working directory for subagents.

Made-with: Cursor

nanobot/agent/tools/spawn.py

@@ -33,7 +33,8 @@ class SpawnTool(Tool):
             "Spawn a subagent to handle a task in the background. "
             "Use this for complex or time-consuming tasks that can run independently. "
             "The subagent will complete the task and report back when done. "
-            "For deliverables or existing projects, inspect the workspace and assign/create a dedicated working directory for the subagent."
+            "For deliverables or existing projects, inspect the workspace first "
+            "and use a dedicated subdirectory when helpful."
         )
 
     @property