feat(desktop): add hyprlock and hypridle (task 0026)

Add a session-lock screen and idle management to the Hyprland-native
subdirectory, enabled through the desktop aggregator.

hyprlock draws through the compositor session-lock protocol, themed by
Stylix, with a centered field and clock. Super+X locks directly through a
guarded launch so the key works without the idle daemon.

hypridle locks on idle and powers the displays off, with tunable timeouts,
and locks before every suspend. Lid-close routes through logind to suspend,
which the pre-sleep lock covers, so the lid lands at a locked screen.

.claude/tasks/0026-hyprlock-and-hypridle.md

@@ -14,8 +14,33 @@ Bind lock on `Super+X`.
 
 ## Acceptance criteria
 
-- [ ] hyprlock and hypridle modules exist in the Hyprland-native subdirectory and are enabled by the aggregator.
+- [x] hyprlock and hypridle modules exist in the Hyprland-native subdirectory and are enabled by the aggregator.
-- [ ] hyprlock uses the compositor session-lock protocol.
+- [x] hyprlock uses the compositor session-lock protocol.
-- [ ] hypridle triggers lock-on-idle, screen-off, lock-before-suspend, and lid-close, with tunable timeouts.
+- [x] hypridle triggers lock-on-idle, screen-off, lock-before-suspend, and lid-close, with tunable timeouts.
-- [ ] Lock is bound on `Super+X`.
+- [x] Lock is bound on `Super+X`.
-- [ ] neogaia builds green under `nix flake check`.
+- [x] neogaia builds green under `nix flake check`.
+
+## Implementation Notes
+
+- **hyprlock is inherently the session-lock client.**
+  Criterion 2 needs no option: hyprlock draws its surface through the ext-session-lock protocol, so the compositor owns the surface and it survives a crash of the locker.
+  The module therefore carries only geometry and behaviour.
+
+- **Stylix themes the lock screen.**
+  Colors and the lock background come from Stylix's hyprlock target, which merges into the same `background` and `input-field` blocks, so the module sets only field geometry and a `$TIME` label.
+
+- **lid-close is wired through logind, not a hypridle listener.**
+  hypridle cannot observe lid events, so the module sets `services.logind.settings.Login.HandleLidSwitch = "suspend"`, and the shared `before_sleep_cmd` locks ahead of the suspend.
+  The lid therefore lands at a locked screen, satisfying the criterion by outcome even though the trigger is logind's.
+
+- **`Super+X` is self-contained.**
+  The keybind execs a guarded hyprlock launch directly (`pidof hyprlock || hyprlock`) rather than `loginctl lock-session`, so the lock key works whenever hyprlock is enabled, without depending on hypridle being the running lock handler.
+  hypridle's own idle and suspend paths still funnel through `loginctl lock-session` so logind tracks the locked state on those paths.
+
+- **Idle-suspend was left out.**
+  The spec enumerates lock-on-idle, screen-off, lock-before-suspend, and lid-close, so hypridle does not itself suspend on idle.
+  `before_sleep_cmd` handles lock-before-suspend for the lid and any manual or externally configured suspend.
+  Adding an idle-suspend stage is a reasonable future knob but was not requested here.
+
+- **One hyprlock package.**
+  Both the keybind and hypridle's `lock_cmd` reference `programs.hyprlock.package`, so the locker never splits versions between the two call sites.

modules/desktop/desktop.nix

@@ -10,6 +10,8 @@ in
   # any one of them while the single flag above enables the whole desktop.
   config = lib.mkIf cfg.enable {
     modules.desktop.hyprland.enable = lib.mkDefault true;
+    modules.desktop.hyprlock.enable = lib.mkDefault true;
+    modules.desktop.hypridle.enable = lib.mkDefault true;
     modules.desktop.login.enable = lib.mkDefault true;
     modules.desktop.mako.enable = lib.mkDefault true;
     modules.desktop.rofi.enable = lib.mkDefault true;

modules/desktop/hyprland/hypridle.nix

@@ -0,0 +1,69 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+# Idle management: hypridle locks on idle, powers the displays off, and locks
+# before every suspend, so an unattended session always lands at hyprlock.
+let
+  cfg = config.modules.desktop.hypridle;
+  user = config.user.name;
+
+  hyprctl = "${config.programs.hyprland.package}/bin/hyprctl";
+  hyprlock = "${config.home-manager.users.${user}.programs.hyprlock.package}/bin/hyprlock";
+
+  # The guard drops the call when a locker is already up, so no idle trigger
+  # stacks a second hyprlock over the first.
+  lockCmd = "${pkgs.procps}/bin/pidof hyprlock || ${hyprlock}";
+in
+{
+  options.modules.desktop.hypridle = {
+    enable = lib.mkEnableOption "hypridle idle management";
+
+    lockTimeout = lib.mkOption {
+      type = lib.types.ints.positive;
+      default = 300;
+      description = "Seconds of inactivity before the screen locks.";
+    };
+
+    screenOffTimeout = lib.mkOption {
+      type = lib.types.ints.positive;
+      default = 360;
+      description = "Seconds of inactivity before the displays are powered off.";
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    # Closing the lid suspends, and every suspend locks first through the
+    # before_sleep_cmd below, so the lid always lands at a locked screen.
+    services.logind.settings.Login.HandleLidSwitch = "suspend";
+
+    home-manager.users.${user}.services.hypridle = {
+      enable = true;
+
+      settings = {
+        general = {
+          lock_cmd = lockCmd;
+          before_sleep_cmd = "loginctl lock-session";
+          # Waking restores the displays the screen-off listener may have cut.
+          after_sleep_cmd = "${hyprctl} dispatch dpms on";
+        };
+
+        listener = [
+          # Lock on idle.
+          {
+            timeout = cfg.lockTimeout;
+            on-timeout = "loginctl lock-session";
+          }
+          # Power the displays off a little later, restoring them on any activity.
+          {
+            timeout = cfg.screenOffTimeout;
+            on-timeout = "${hyprctl} dispatch dpms off";
+            on-resume = "${hyprctl} dispatch dpms on";
+          }
+        ];
+      };
+    };
+  };
+}

modules/desktop/hyprland/hyprlock.nix

@@ -0,0 +1,61 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+# The lock screen: hyprlock, a session-lock client whose surface the compositor owns, so it survives a crash of the locker rather than exposing the session.
+let
+  cfg = config.modules.desktop.hyprlock;
+  user = config.user.name;
+
+  # The hyprlock this module installs, so the keybind and the idle daemon lock
+  # with one package and never split versions.
+  hyprlock = "${config.home-manager.users.${user}.programs.hyprlock.package}/bin/hyprlock";
+in
+{
+  options.modules.desktop.hyprlock.enable = lib.mkEnableOption "the hyprlock lock screen";
+
+  config = lib.mkIf cfg.enable {
+    home-manager.users.${user} = {
+      # Colors and the lock-screen background come from Stylix's hyprlock target,
+      # so only geometry and behaviour are set here.
+      programs.hyprlock = {
+        enable = true;
+
+        settings = {
+          general = {
+            hide_cursor = true;
+            # No progress bar flashes before the field is ready to take input.
+            disable_loading_bar = true;
+          };
+
+          # A centered password field; its colors are the Stylix target's.
+          input-field = {
+            size = "260, 52";
+            rounding = 8;
+            position = "0, -100";
+            halign = "center";
+            valign = "center";
+          };
+
+          # The current time, above the field.
+          label = {
+            text = "$TIME";
+            font_size = 48;
+            position = "0, 120";
+            halign = "center";
+            valign = "center";
+          };
+        };
+      };
+
+      # Lock on Super+X.
+      # The guard drops the keypress when a locker is already up, so a second
+      # hyprlock never stacks over the first.
+      wayland.windowManager.hyprland.settings.bind = [
+        "$mod, X, exec, ${pkgs.procps}/bin/pidof hyprlock || ${hyprlock}"
+      ];
+    };
+  };
+}