[Bug] v2.0.6: skill-registry BigInt type error breaks all requests (REQUEST_EXTENSION failed)

[Solxf]

Bug description

DSH Desktop v2.0.6 上所有对话都失败，新会话、换模型、换权限预设都无法解决。

错误提示：

本轮运行失败 DeepSeek request extension preparation failed
错误阶段：REQUEST_EXTENSION

Environment

• OS: Windows
• DSH Desktop version: v2.0.6
• Mode: compatibility (兼容模式)
• Default model: deepseek-v4-flash (reasoningEffort: max)
• Profile: desktop
• Date: 2026-09-10

Steps to reproduce

1. Install / update to DSH Desktop v2.0.6
2. Start the app, create a new session
3. Send any message (e.g. "你好")
4. Immediately see "DeepSeek request extension preparation failed"

Expected behavior

Messages should be sent and model should respond normally.

Actual behavior

Every single request fails with "request extension preparation failed", regardless of:

• New sessions vs existing sessions
• Different models (Flash High / Flash Max)
• Different permission presets (danger-full-access / workspace-write)
• Standard mode vs creative mode

Diagnostic logs

Key error from dsh-YYYY-MM-DD.error.log: