dsh-governed-workflow: Add task authorization, lifecycle, and acceptance boundaries to DSH

dsh-governed-workflow is a community plugin designed for DeepSeek Harness agents, aimed at addressing task boundary drift and permission abuse in agent development. Its core philosophy is to shift agent workflows from direct modification to a strict sequence of "confirming permissions, controlled execution, and independent verification." The plugin introduces a task authority mechanism based on public GitHub Issues and implements lifecycle state machine management (Observing, Admission, Running, Blocked/Completed, Pending Review). Key features include a "RUNNING-only modification guard," which means that sensitive operations such as bash, write, and edit are only allowed when the task is in the RUNNING state and authority is valid; after the task enters a terminal state, modification permissions are automatically frozen, and will...