Add Omarchy-style Hyprland desktop for straylight

Ports the classic dotfiles Omarchy setup to a no-home-manager NixOS
system module (configs/omarchy.nix), scoped to straylight only so the
other desktop hosts keep i3.

- Hyprland (programs.hyprland) becomes the default lightdm session; i3
  stays enabled and selectable as a fallback.
- Omarchy config layout under ~/.config/{hypr,waybar,rofi,wlogout,
  swayosd,alacritty} symlinked from the store; mutable theme/wallpaper
  state in ~/.config/omarchy/current.
- omarchy-dots generates 8 themes (hyprland/hyprlock/waybar/rofi/
  swayosd/wlogout/alacritty/mako colour files) from each theme's
  palette, with wallpapers fetched from the Omarchy v3.8.4 tag.
- Helper scripts: omarchy-theme-set/bg-next/bg-set/apply, omarchy-menu
  (rofi power/theme/background menus), waybar toggle, screenshot, lock.
- Shared desktop modules (desktop.nix / desktop-light.nix) untouched.

configs/omarchy/waybar/config.jsonc

@@ -0,0 +1,117 @@
+{
+  "reload_style_on_change": true,
+  "layer": "top",
+  "position": "top",
+  "spacing": 0,
+  "height": 26,
+  "modules-left": ["custom/omarchy", "hyprland/workspaces"],
+  "modules-center": ["clock"],
+  "modules-right": ["tray", "bluetooth", "network", "pulseaudio", "cpu", "battery"],
+
+  "custom/omarchy": {
+    "format": "\uf0c9",
+    "on-click": "omarchy-menu",
+    "on-click-right": "alacritty",
+    "tooltip-format": "Omarchy Menu\n\nSuper + Alt + Space"
+  },
+
+  "hyprland/workspaces": {
+    "on-click": "activate",
+    "format": "{icon}",
+    "format-icons": {
+      "default": "<span size='small'></span>",
+      "1": "1",
+      "2": "2",
+      "3": "3",
+      "4": "4",
+      "5": "5",
+      "6": "6",
+      "7": "7",
+      "8": "8",
+      "9": "9",
+      "10": "0",
+      "active": "󱓻"
+    },
+    "persistent-workspaces": {
+      "1": [],
+      "2": [],
+      "3": [],
+      "4": [],
+      "5": []
+    }
+  },
+
+  "clock": {
+    "format": "{:%A %H:%M}",
+    "format-alt": "{:%d %B W%V %Y}",
+    "tooltip": false
+  },
+
+  "cpu": {
+    "interval": 5,
+    "format": "󰍛",
+    "on-click": "alacritty -e btop"
+  },
+
+  "network": {
+    "format-icons": ["󰤯", "󰤟", "󰤢", "󰤥", "󰤨"],
+    "format": "{icon}",
+    "format-wifi": "{icon}",
+    "format-ethernet": "󰀂",
+    "format-disconnected": "󰤮",
+    "tooltip-format-wifi": "{essid} ({frequency} GHz)",
+    "tooltip-format-ethernet": "Connected",
+    "tooltip-format-disconnected": "Disconnected",
+    "interval": 3,
+    "spacing": 1,
+    "on-click": "nm-connection-editor"
+  },
+
+  "battery": {
+    "interval": 5,
+    "format": "{capacity}% {icon}",
+    "format-discharging": "{icon}",
+    "format-charging": "{icon}",
+    "format-plugged": "󰂅",
+    "format-icons": {
+      "charging": ["󰢜", "󰂆", "󰂇", "󰂈", "󰢝", "󰂉", "󰢞", "󰂊", "󰂋", "󰂅"],
+      "default": ["󰁺", "󰁻", "󰁼", "󰁽", "󰁾", "󰁿", "󰂀", "󰂁", "󰂂", "󰁹"]
+    },
+    "format-full": "󰂅",
+    "tooltip-format-discharging": "{power:>1.0f}W↓ {capacity}%",
+    "tooltip-format-charging": "{power:>1.0f}W↑ {capacity}%",
+    "states": {
+      "warning": 20,
+      "critical": 10
+    },
+    "on-click": "omarchy-menu system"
+  },
+
+  "bluetooth": {
+    "format": "󰂯",
+    "format-off": "󰂲",
+    "format-disabled": "󰂲",
+    "format-connected": "󰂱",
+    "tooltip-format": "Devices connected: {num_connections}",
+    "on-click": "blueman-manager"
+  },
+
+  "pulseaudio": {
+    "format": "{icon}",
+    "on-click": "pavucontrol",
+    "on-click-right": "pamixer -t",
+    "tooltip-format": "Playing at {volume}%",
+    "scroll-step": 5,
+    "format-muted": "󰝟",
+    "format-icons": {
+      "headphone": "󰋋",
+      "headset": "󰋎",
+      "default": ["󰕿", "󰖀", "󰕾"]
+    }
+  },
+
+  "tray": {
+    "icon-size": 12,
+    "spacing": 17
+  }
+}

configs/omarchy/waybar/style.css

@@ -0,0 +1,63 @@
+@import "../omarchy/current/theme/waybar.css";
+
+* {
+  background-color: @background;
+  color: @foreground;
+
+  border: none;
+  border-radius: 0;
+  min-height: 0;
+  font-family: 'JetBrainsMono Nerd Font';
+  font-size: 12px;
+}
+
+.modules-left {
+  margin-left: 8px;
+}
+
+.modules-right {
+  margin-right: 8px;
+}
+
+#workspaces button {
+  all: initial;
+  padding: 0 6px;
+  margin: 0 1.5px;
+  min-width: 9px;
+}
+
+#workspaces button.empty {
+  opacity: 0.5;
+}
+
+#cpu,
+#battery,
+#pulseaudio,
+#custom-omarchy {
+  min-width: 12px;
+  margin: 0 7.5px;
+}
+
+#tray {
+  margin-right: 16px;
+}
+
+#bluetooth {
+  margin-right: 17px;
+}
+
+#network {
+  margin-right: 13px;
+}
+
+tooltip {
+  padding: 2px;
+}
+
+#clock {
+  margin-left: 8.75px;
+}
+
+.hidden {
+  opacity: 0;
+}