restructure

- users/rin/default.nix -> users/rin.nix
- users/rin/home.nix +-> users/rin.nix
- users/rin/*.nix -> modules/user/*.nix
- users/rin/scripts/ -> scripts/
- hosts/winter/default.nix -> hosts/winter.nix
- hosts/winter/*.nix -> modules/system/*.nix

- modules are dynamically imported as sets for system and user

modules/user/bspwm.nix

@@ -0,0 +1,16 @@
+{ config, ... }: {
+  xsession.windowManager.bspwm = {
+    enable = true;
+    monitors = { eDP-1 = [ "I" "II" "III" "IV" "V" "VI" "VII" "VIII" "XI" "X" ]; };
+    settings = {
+      window_gap = 10;
+      border_width = 0;
+      split_ratio = 0.5;
+      top_padding = 25;
+    };
+    extraConfig = ''
+      feh --no-fehbg --bg-fill ${config.xdg.configHome}/xorg/wallpaper.png
+      systemctl --user restart polybar # home-manager loads this too early
+    '';
+  };
+}