fix(desktop): unfree CLI default, bar icon spacing, unified clock

Hardware findings on Latitude: nix-shell blocked unfree; whole-swap
bars collided icon+percentage; clock needed calcurse + one module.

- Export NIXPKGS_ALLOW_UNFREE=1 + ~/.config/nixpkgs/config.nix
- Mono Nerd face + trailing spaces on battery/volume icons (all bars)
- Single clock `HH:MM · Day DD Mon`; calcurse ships with waybar
- V3 queue entries for laptop re-check

Verification: V0 — nix flake check --no-build green; V2/V3 pending on
session (user-visible bar + CLI unfree).

modules/home/default.nix

@@ -66,6 +66,9 @@
   home.sessionVariables = {
     TERMINAL = config.nomarchy.terminal;
     NIXOS_OZONE_WL = "1"; # Electron/Chromium native Wayland
+    # Same gate as modules/nixos: CLI nix-shell/shell/run for unfree pkgs
+    # (system nixpkgs.config alone does not cover those entry points).
+    NIXPKGS_ALLOW_UNFREE = "1";
 
     # Where the Nomarchy flake (and therefore theme-state.json) lives on
     # disk. nomarchy-theme-sync writes its state here; rebuilds read from
@@ -73,5 +76,12 @@
     NOMARCHY_PATH = "$HOME/.nomarchy";
   };
 
+  # Classic nix-shell / nix-env read this; pairs with NIXPKGS_ALLOW_UNFREE
+  # above so "allow unfree" is the default desktop experience, not a
+  # per-command export the user has to remember.
+  xdg.configFile."nixpkgs/config.nix".text = ''
+    { allowUnfree = true; }
+  '';
+
   programs.home-manager.enable = true;
 }