dsh-live-preset-switch: Live Agent Preset Switching Guidance Bundle

`dsh-live-preset-switch` is a standard Bundle of DeepSeek Harness (DSH), designed to provide guidance on “turn-boundary preset switching” for Live Agent scenarios. It explicitly explains Agent preset selection logic and switching behavior by adding entries to Profiles and registering built-in Skills. The component is designed for purely incremental installation, has no runtime dependencies, does not interfere with core DSH components, and is compatible with specific DSH and Node versions.