dsh-toolkit: One command to equip DSH with MCP management, Skill management, and Git branch badges

# Introduction If you are using the DeepSeek Harness (DSH) web client, you are likely familiar with the following operations: configuring MCP servers requires manually editing `$DSH_HOME/profiles/web/cordis.patch.yml`; adding or removing Skills requires directly modifying Markdown files under `$DSH_HOME/skills`; and checking which git branch the current session is running on requires switching back to the terminal. These tasks are not difficult in themselves, but because they are scattered outside the client, the overhead of switching back and forth is significant. dsh-toolkit aims to solve this problem by packaging three functions—MCP management, Skill management, and Git branch badges—into a plugin toolkit.