fix(exec): detach stdin for shell commands

nanobot/agent/tools/shell.py

@@ -266,6 +266,7 @@ class ExecTool(Tool):
             # the raw command string to COMSPEC without re-quoting.
             return await asyncio.create_subprocess_shell(
                 command,
+                stdin=asyncio.subprocess.DEVNULL,
                 stdout=asyncio.subprocess.PIPE,
                 stderr=asyncio.subprocess.PIPE,
                 cwd=cwd,
@@ -274,6 +275,7 @@ class ExecTool(Tool):
         bash = shutil.which("bash") or "/bin/bash"
         return await asyncio.create_subprocess_exec(
             bash, "-l", "-c", command,
+            stdin=asyncio.subprocess.DEVNULL,
             stdout=asyncio.subprocess.PIPE,
             stderr=asyncio.subprocess.PIPE,
             cwd=cwd,