Add Tailscale plugin and enable on desktop/laptop

- Enable Tailscale plugin in home modules for Garand-Desktop and
  Garand-Laptop; keep it disabled in the default host.
- Introduce `tailscale.enable` option in noctalia plugins and add
  it to the noctalia-shell configuration with source URL handling.
- Provide default Tailscale settings (refresh interval, UI options,
  Taildrop configuration, login server, etc.).
- Add Tailscale widget to the right side of the bar widget list.
- Bump Helium AppImage to version 0.12.5.1 and update its sha256.

hosts/Garand-Desktop/home-modules.nix

@@ -78,5 +78,6 @@ _: {
     screen-recorder.enable = true; # Screen Recorder: Hardware-accelerated screen recording using gpu-screen-recorder with customizable video and audio settings
     screenshot.enable = true; # Screenshot: Quick screenshot button in bar for Hyprland, Sway, and Niri
     ntfy-notifications.enable = true; # ntfy Notifications: Subscribe to ntfy topics and receive push notifications directly in your bar, with full theming support
+    tailscale.enable = true; # Tailscale: Show Tailscale status in the menu bar and send/receive files via Taildrop.
   };
 }

hosts/Garand-Laptop/home-modules.nix

@@ -78,5 +78,6 @@ _: {
     screen-recorder.enable = false; # Screen Recorder: Hardware-accelerated screen recording using gpu-screen-recorder with customizable video and audio settings
     screenshot.enable = true; # Screenshot: Quick screenshot button in bar for Hyprland, Sway, and Niri
     ntfy-notifications.enable = true; # ntfy Notifications: Subscribe to ntfy topics and receive push notifications directly in your bar, with full theming support
+    tailscale.enable = true; # Tailscale: Show Tailscale status in the menu bar and send/receive files via Taildrop.
   };
 }

hosts/default/home-modules.nix

@@ -78,5 +78,6 @@ _: {
     screen-recorder.enable = false; # Screen Recorder: Hardware-accelerated screen recording using gpu-screen-recorder with customizable video and audio settings
     screenshot.enable = false; # Screenshot: Quick screenshot button in bar for Hyprland, Sway, and Niri
     ntfy-notifications.enable = false; # ntfy Notifications: Subscribe to ntfy topics and receive push notifications directly in your bar, with full theming support
+    tailscale.enable = false; # Tailscale: Show Tailscale status in the menu bar and send/receive files via Taildrop.
   };
 }