dsh-plugin-discussion-intent: DSH Discussion Mode

DSH `dsh-plugin-discussion-intent` is a Discussion Mode plugin designed to prevent drift in complex AI conversations. It continuously injects user intent, boundaries, and evaluation criteria to ensure the conversation remains coherent and goal-oriented. Core features include preventing intent drift, allowing sub-agents to select their own models, deep settings that move from vague to actionable, on-the-fly course correction via a four-line Rail, and support for continuing discussions. The plugin depends on DSH 0.1.0-rc.6, supports checkpoint persistence, and can be controlled through the `/discussion` command to manage discussion depth, model, and status.