Move the Docker sandbox Java documentation from docs-site to the
appropriate location in docs/users/features/sandbox.md under the
Troubleshooting section.
Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>
Fixes#1359.
Default container sandboxing on Linux to use host UID/GID so qwen runs under a user that matches the mounted home directory and persists auth/settings in ~/.qwen.
Also gate the informational log behind DEBUG/DEBUG_MODE and clarify docs about Linux UID/GID mapping and ~/.qwen persistence.