Interactive docking plug-in with DSH ACP

Key features

• The tool is mounted through @deepseek-ai/dsh-tool-subagent, and the tool name seen by the model defaults to subagent_bitfun.
• Any session in dsh can use the subagent_bitfun tool to delegate tasks to BitFun for execution.
• Confirm the plug-in line in the dsh configuration tree
• When the task ends, the subprocess stdin is closed (EOF grace 6s → SIGTERM → SIGKILL), the BitFun subprocess exits immediately under SIGTERM, and the session data is persisted by BitFun itself.
• Have the model call the subagent_bitfun tool in a dsh session, delegate a simple task (such as "reply hello with subagent_bitfun"), and confirm that the output of BitFun is returned.