dsh-model-memory: Supplementing DSH with persistent memory for custom model reasoning levels and channel preferences

dsh-model-memory is a DSH plugin developed by Mutx163, designed to address the issue of missing thinking level configurations for custom API models and the loss of model and thinking strength preferences when switching channels. It mounts a thinking level configuration bar for custom models within the official "Settings -> Models" section, supports low/medium/high/max levels, and allows for hot-reloading of configurations. Additionally, it remembers the last selected model and thinking intensity across sessions per channel, ensuring preferences are preserved when switching channels.