docs(docs): add iris docs and update shell documentation for iris integration

docs/shell/meta.ts

@@ -3,5 +3,5 @@ import { defineMeta } from "blume";
 export default defineMeta({
   title: "Shell",
   icon: "terminal",
-  pages: ["index", "fish", "bash-zsh", "aliases", "scripts", "starship", "atuin"],
+  pages: ["index", "fish", "bash-zsh", "aliases", "scripts", "starship", "iris", "atuin"],
 });