revert(shell): move iris integration to the iris branch

Reverts 43dfe48, 0692ae3, e0cdcd6 and the cable-description half of
098da70 (the star-prompt stats stay). master returns to the pre-iris
shell setup: atuin in fish/zsh/bash, the down -> pj binding with
PJ_QUIET, and the fish/zsh key bindings as they were. The iris work
lives on the `iris` branch.

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", "iris", "atuin"],
+  pages: ["index", "fish", "bash-zsh", "aliases", "scripts", "starship", "atuin"],
 });