Feature request: clipboard history sync (wl-clipboard integration)

I already use and love atuin for shell history sync across machines. It would be amazing if atuin could also manage clipboard history, integrating with `wl-clipboard` (via `wl-paste --watch`) on Wayland. Currently I'm using [cliphist](https://github.com/sentriz/cliphist) for local clipboard history, but it's local-only with no sync or encryption. Atuin already has all the infrastructure in place -- encrypted sync, server/client architecture, configurable retention, and a great search UI. Adding clipboard history as a second store alongside shell history seems like a natural extension. The basic idea: - Listen for clipboard changes via `wl-paste --watch` (Wayland) or similar on X11 - Store entries in atuin's existing database - Sync clipboard history across machines just like shell history - Search/recall via `atuin search` or the interactive UI Would love to hear your thoughts on whether this fits atuin's scope!