feat: refactor, update settings for sunshine (#215)

modules/nixos/desktop/networking/tailscale.nix

@@ -0,0 +1,46 @@
+{
+  config,
+  pkgs,
+  ...
+}:
+# =============================================================
+#
+# Tailscale - your own private network(VPN) that uses WireGuard
+#
+# It's open source and free for personal use,
+# and it's really easy to setup and use.
+# Tailscale has great client coverage for Linux, windows, Mac, android, and iOS.
+# Tailscale is more mature and stable compared to other alternatives such as netbird/netmaker.
+# Maybe I'll give netbird/netmaker a try when they are more mature, but for now, I'm sticking with Tailscale.
+#
+# How to use:
+#  1. Create a Tailscale account at https://login.tailscale.com
+#  2. Login via `tailscale login`
+#  3. join into your Tailscale network via `tailscale up --accept-routes`
+#  4. If you prefer automatic connection to Tailscale, use the `authKeyFile` option` in the config below.
+#
+# Status Data:
+#   `journalctl -u tailscaled` shows tailscaled's logs
+#   logs indicate that tailscale store its data in /var/lib/tailscale
+#   which is already persistent across reboots(via preservation)
+#
+# References:
+# https://github.com/NixOS/nixpkgs/blob/nixos-25.05/nixos/modules/services/networking/tailscale.nix
+#
+# =============================================================
+{
+  # make the tailscale command usable to users
+  environment.systemPackages = [ pkgs.tailscale ];
+
+  # enable the tailscale service
+  services.tailscale = {
+    enable = true;
+    port = 41641;
+    interfaceName = "tailscale0";
+    # allow the Tailscale UDP port through the firewall
+    openFirewall = true;
+    useRoutingFeatures = "client";
+    extraUpFlags = "--accept-routes";
+    # authKeyFile = "/var/lib/tailscale/authkey";
+  };
+}