fix: make base modules enabled by default; document lazylib→lazygit

- All base/* modules now use (mkEnableOption "...") // { default = true; }
  so they activate automatically when imported — no explicit .enable = true
  required in host configs
- packages.nix: add comment documenting that lazylib does not exist in
  nixpkgs; lazygit is the correct and intended package
- zellij-ps.nix: clarify that cli.zellij-ps namespace is intentional —
  it is the home-manager module convention from m3ta-nixpkgs
- nix flake check passes (warnings are pre-existing)

home/base/cli-tools/zellij.nix

@@ -7,7 +7,8 @@
 with lib; let
   cfg = config.base.cliTools.zellij;
 in {
-  options.base.cliTools.zellij.enable = mkEnableOption "enable zellij multiplexer";
+  # Enabled by default — base modules are always-on.
+  options.base.cliTools.zellij.enable = (mkEnableOption "enable zellij multiplexer") // {default = true;};
 
   config = mkIf cfg.enable {
     programs.zellij = {