phosh: statically configure a few dconf settings (experimental)

hosts/common/default.nix

@@ -75,6 +75,19 @@
     # LIBGL_ALWAYS_SOFTWARE = "1";
   };
 
+  # dconf docs: <https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/desktop_migration_and_administration_guide/profiles>
+  programs.dconf.enable = true;
+  programs.dconf.packages = [
+    (pkgs.writeTextFile {
+      name = "dconf-user-profile";
+      destination = "/etc/dconf/profile/user";
+      text = ''
+        user-db:user
+        system-db:site
+      '';
+    })
+  ];
+
   # link debug symbols into /run/current-system/sw/lib/debug
   # hopefully picked up by gdb automatically?
   environment.enableDebugInfo = true;

hosts/modules/gui/phosh.nix

@@ -59,6 +59,21 @@ in
         NIXOS_OZONE_WL = "1";
       };
 
+      programs.dconf.packages = [
+        (pkgs.writeTextFile {
+          name = "dconf-phosh-settings";
+          destination = "/etc/dconf/db/site.d/00_phosh_settings";
+          text = ''
+            [org/gnome/desktop/interface]
+            show-battery-percentage=true
+
+            [org/gnome/settings-daemon/plugins/power]
+            sleep-inactive-ac-timeout=5400
+            sleep-inactive-battery-timeout=5400
+          '';
+        })
+      ];
+
       sane.packages.extraUserPkgs = with pkgs; [
         phosh-mobile-settings