dsh-bedtime: Bedtime Ritual

The DSH plugin `dsh-bedtime` is a lightweight functional plugin for generating “bedtime routine” suggestions during agent construction or session management. Implemented in pure Node.js, it runs entirely locally without any network dependencies. It accepts parameters and returns routine suggestions, requiring a specific version of the DSH environment. Users can install it via the `dsh plugin add` command, making it suitable for scenarios that programmatically generate bedtime routine suggestions.