devshells(cli): add additional .envrc

Auto load the rust environment devshell upon entering the cli source
tree.

Author: nrdxp

nix/automation/devshells.nix

@@ -33,7 +33,7 @@ in {
       capsules.hooks
     ];
   };
-  dev = std.lib.mkShell {
+  cli = std.lib.mkShell {
     packages = rust-dev-pkgs;
     language.rust = {
       packageSet = rustPlatform;

nix/cli/packages/cli/.envrc

@@ -0,0 +1,4 @@
+#! /bin/sh
+
+. "$(nix eval .#__std.direnv_lib)"
+use std nix //automation/devshells:cli