[Bug]: 工具调用404

## QwenPaw Version

2.1.0

## Description

/api/tool-calls/1785293416841-59njx7u/call_8b24348545b745cda6743348
流式会话时，页面一直在调用@router.post("/{session_id}/{tool_call_id}/offload", status_code=202)接口，接口响应：404 {"detail":"Tool call not found"}

## Component(s) Affected

- [ ] Core / Backend (app, agents, config, providers, utils, local_models)
- [ ] Console (frontend web UI)
- [ ] Channels (DingTalk, Feishu, QQ, Discord, iMessage, etc.)
- [ ] Skills
- [ ] CLI
- [ ] Documentation (website)
- [ ] Tests
- [ ] CI/CD
- [ ] Scripts / Deploy

## Environment

- **QwenPaw version:2.1。0

## Steps to Reproduce

1.创建会话
2.让agnet去优化已经生成的ppt，执行skill时就假死了
tool_call_id: call_8b24348545b745cda6743348
tool: execute_shell_command
command: cd /root/.qwenpaw/workspaces/ppt && python -m markitdown "media/5e6f6fd702bc43d38fa3fa16d4e4d047_服务器ST02交付材料-容器集群运维报告-2024年01月.pptx" 2>/dev/null | head -200

## Actual vs Expected

- **Actual:**
- **Expected:**

## Logs / Screenshots

[Paste relevant log output or attach screenshots. Use code blocks for logs.]

```
(paste logs here)
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## Additional Notes

[Optional: workarounds, similar issues, etc.]

Start by tracing the POST /api/tool-calls/{session_id}/{tool_call_id}/offload route mentioned in the report and the tool-call lifecycle around it. Reproduce the PPT optimization workflow with execute_shell_command, then compare the reported 404 response with the request's session and tool-call identifiers; done should mean the skill no longer hangs, though the issue does not define an expected response beyond avoiding this failure.

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