dsh-multi-folder: Adding Secondary Working Directories for DeepSeek Harness

dsh-multi-folder is an MIT-licensed plugin for DeepSeek Harness (DSH), maintained by AngelosZou. It is designed to address the issue of frequently switching between multiple workspaces when developing simultaneously across multiple repositories (source code, tests, documentation). The plugin allows configuring a set of secondary working directories without altering the core attributes of the primary workspace, enabling agents to read, write, and execute operations on these secondary directories within the same session. Core functionalities include granting secondary directories the same permissions as the primary directory in `workspace-write` mode and overriding the execution root directories for `write`, `edit`, and shell commands through framework-level interception.