dsh-minimal-anchor: Minimal Toolset for DSH Round 1

`dsh-minimal-anchor` is a DeepSeek Harness plugin designed to address prompt overload in the first turn caused by sending the full tool list. It prunes tools using a whitelist and injects a structured preamble only in the first turn to guide the model to focus on analysis; from the second turn onward, it restores the full tool set. Developers can enable it by installing the plugin and adding it to the profile's `bundles` list. The config file allows customizing the whitelisted tools and preamble content. This plugin is released under the MIT license and is suitable for users who want to optimize the initial phase of a conversation.