dsh-exec-extension: A One-Time Execution Bundle for DeepSeek Harness

`dsh-exec-extension` is a one-off task execution plugin for DeepSeek Harness (DSH) that allows users to inject tasks and configurations directly via the CLI without requiring persistent files. Maintained by LvDAO, it overrides the default `headless-startup` logic and supports task input (including files), streaming session output, runtime configuration, and model tool overrides. It is particularly suited for quick invocation scenarios such as code analysis, but does not support advanced features like MCP or Host.