dsh-access-mode: DeepSeek Harness Session Access Mode Plugin

`dsh-access-mode` is a plugin for DeepSeek Harness (DSH) designed to address the limitations of native permission preset balance and the high cost of modifying core code. By providing three session-level access modes—Default / No Edit / Auto—it enables users to finely control the AI’s tool invocations, sandbox policies, and approval policies without modifying the core code of Harness. **Core features**: non-intrusive integration, reuse of native services, and session persistence support. **Mode descriptions**: Default uses a conservative `workspace-write` boundary; No Edit removes file restrictions while only restricting editing; Auto fully permits access. **Security note**: No Edit and