refactor(shell): move agent tools into shell modules

configs/nixos/hosts/neogaia/default.nix

@@ -42,8 +42,8 @@
 
   modules.monorepo.enable = true;
   modules.shell.herdr.enable = true;
-  modules.agents.tools.gitea-axi.enable = true;
+  modules.shell.gitea-axi.enable = true;
-  modules.agents.pi.enable = true;
+  modules.shell.pi.enable = true;
 
   modules.desktop.enable = true;
   modules.desktop.apps.obsidian.enable = true;

configs/nixos/modules/shell/gitea-axi.nix

@@ -6,11 +6,11 @@
 }:
 # gitea-axi for the primary user, installed through its own home-manager module.
 let
-  cfg = config.modules.agents.tools.gitea-axi;
+  cfg = config.modules.shell.gitea-axi;
   user = config.user.name;
 in
 {
-  options.modules.agents.tools.gitea-axi.enable =
+  options.modules.shell.gitea-axi.enable =
     lib.mkEnableOption "gitea-axi, an agent-ergonomic CLI for Gitea issues and pull requests";
 
   config = lib.mkIf cfg.enable {

configs/nixos/modules/shell/pi/default.nix

@@ -8,7 +8,7 @@
 # home-manager, which ships the package and manages global settings.
 # The login credential is left unmanaged, so it survives rebuilds.
 let
-  cfg = config.modules.agents.pi;
+  cfg = config.modules.shell.pi;
   user = config.user.name;
   piDir = "${config.users.users.${user}.home}/.pi/agent";
   patchedPi = pkgs.pi-coding-agent.overrideAttrs (old: {
@@ -19,7 +19,7 @@ let
   });
 in
 {
-  options.modules.agents.pi = {
+  options.modules.shell.pi = {
     enable = lib.mkEnableOption ''
       Pi, a terminal coding agent, configured via home-manager'';
   };