dsh-agency-agents-zh: 267 Plug-and-Play AI Expert Roles

The DeepSeek Harness (DSH) plugin `dsh-agency-agents-zh` provides 267 plug-and-play AI expert role definitions covering 19 domains, such as engineering and marketing. It is ported verbatim from the upstream project, with files byte-for-byte identical to upstream v1.2.7. The plugin supports on-demand loading and has zero dependencies. Once installed, it can be used without configuration. Users can explicitly invoke a role by entering `/role-id` in the input, or let the model match roles automatically during the conversation.