dsh-atuin: Record every prompt from DSH into atuin history

dsh-atuin is a DSH plugin (author RealAlexandreAI, v0.1.1, MIT licensed) that writes prompts input through the DSH web interface into the Atuin shell history database. It shares the same history as shell commands, enabling direct search and backtracking via `atuin search` and `Ctrl-R`. The mechanism involves listening to user/message events for sessions/events and executing `atuin history start/end` commands for each input.