feat(system): professionalize system configurations

- Consolidate imperative system settings into /etc/nixos/state.json
- Implement nomarchy.system options for DNS, Wifi powersave, Timezone, and hardware features
- Add declarative browser policies for Chromium/Brave based on theme
- Update toggles scripts to mutate system JSON and run sys-update --impure
- Remove obsolete imperative browser theme and redundant system modules

modules/system/options.nix

@@ -0,0 +1,50 @@
+{ lib, ... }:
+
+{
+  options.nomarchy.system = {
+    dns = lib.mkOption {
+      type = lib.types.enum [ "Cloudflare" "Google" "DHCP" "Custom" ];
+      default = "DHCP";
+      description = "Selected DNS provider.";
+    };
+    customDns = lib.mkOption {
+      type = lib.types.listOf lib.types.str;
+      default = [];
+      description = "List of custom DNS servers.";
+    };
+    wifi = {
+      powersave = lib.mkOption {
+        type = lib.types.bool;
+        default = true;
+        description = "Whether to enable wifi power saving.";
+      };
+    };
+    timezone = lib.mkOption {
+      type = lib.types.str;
+      default = "UTC";
+      description = "System timezone.";
+    };
+    features = {
+      fingerprint = lib.mkOption {
+        type = lib.types.bool;
+        default = false;
+        description = "Whether to enable fingerprint support.";
+      };
+      fido2 = lib.mkOption {
+        type = lib.types.bool;
+        default = false;
+        description = "Whether to enable FIDO2 support.";
+      };
+      hybridGPU = lib.mkOption {
+        type = lib.types.bool;
+        default = false;
+        description = "Whether to enable hybrid GPU support (supergfxd).";
+      };
+    };
+    theme = lib.mkOption {
+      type = lib.types.str;
+      default = "nord";
+      description = "Selected system theme.";
+    };
+  };
+}