hyprland: fix Lua config errors caused by stylix's Hyprland target

Stylix's Hyprland target injects settings.{general,decoration,group,misc}
as top-level keys.  In hyprlang mode these render as section blocks, but
in Lua mode (configType = "lua") they become hl.general(), hl.decoration(),
etc. — functions that don't exist, causing an emergency-mode config error.

Disable stylix.targets.hyprland and absorb all its colours into
settings.config.{general,decoration,group,misc} where they are correctly
rendered inside the single hl.config({}) call.

Also add a home.activation script that removes any stale hyprland.conf
(auto-generated by Hyprland before hyprland.lua was first placed) so the
autogenerated-config warning banner can never persist across restarts.
Keep services.hyprpaper.enable = true since it was previously set by the
now-disabled Hyprland target.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

settings/hyprland.nix

@@ -94,7 +94,21 @@ in
       polkit_gnome
     ];
 
-    home-manager.users.fred = { config, lib, pkgs, inputs, ... }: {
+    home-manager.users.fred = { config, lib, pkgs, inputs, ... }:
+    let
+      c    = config.lib.stylix.colors;
+      rgb  = hex: "rgb(${hex})";
+      rgba = hex: a: "rgba(${hex}${a})";
+    in {
+      # Stylix's Hyprland target injects settings.{general,decoration,group,misc}
+      # as top-level keys, which render as hl.general()/hl.decoration()/… in Lua
+      # mode — functions that don't exist.  Disable it and absorb the colours
+      # into settings.config below.
+      stylix.targets.hyprland.enable = false;
+
+      # Hyprpaper was previously started by stylix's Hyprland target; keep it.
+      services.hyprpaper.enable = true;
+
       wayland.windowManager.hyprland = {
         enable = true;
         configType = "lua";
@@ -111,6 +125,8 @@ in
               border_size = 2;
               layout = "dwindle";
               resize_on_border = true;
+              "col.active_border"   = rgb c.base0D;
+              "col.inactive_border" = rgb c.base03;
             };
 
             decoration = {
@@ -118,6 +134,18 @@ in
               blur = {
                 enabled = true;
               };
+              shadow.color = rgba c.base00 "99";
+            };
+
+            group = {
+              "col.border_active"        = rgb c.base0D;
+              "col.border_inactive"      = rgb c.base03;
+              "col.border_locked_active" = rgb c.base0C;
+              groupbar = {
+                text_color    = rgb c.base05;
+                "col.active"  = rgb c.base0D;
+                "col.inactive" = rgb c.base03;
+              };
             };
 
             render = {
@@ -157,6 +185,7 @@ in
               # show as urgent in the bar instead.
               focus_on_activate = false;
               vrr = 2;
+              background_color = rgb c.base00;
             };
 
             # vfr moved from misc: to debug: in 0.55.0
@@ -560,6 +589,14 @@ in
           #battery.critical { color: @base08; }
         '';
       };
+
+      # The old hyprlang hyprland.conf (with `# autogenerated = 1`) is not
+      # managed by HM after switching to configType = "lua", so Hyprland still
+      # finds it and shows the "autogenerated config" banner. Remove it once on
+      # every activation so it can never linger.
+      home.activation.removeOldHyprlandConf = lib.hm.dag.entryAfter [ "writeBoundary" ] ''
+        rm -f "${config.xdg.configHome}/hypr/hyprland.conf"
+      '';
     };
   };
 }