Move Night Light onto a first-party nightlight service

Same treatment as Stay Awake: the indicator polled the toggle CLI over
a Process with a timer to paper over the race after clicking, and the
CLI ended by asking the shell to refresh every indicator over IPC. A new
omarchy.nightlight service owns hyprsunset instead - it probes the
temperature on startup, applies changes itself for in-shell toggles, and
answers on the nightlight IPC target. The indicator becomes a plain
binding. The CLI still drives hyprctl directly so keybindings, the menu,
and ssh work without the shell, but now just nudges the service to
re-probe since hyprsunset has no state file to watch.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

shell/plugins/services/nightlight/manifest.json

@@ -0,0 +1,14 @@
+{
+  "schemaVersion": 1,
+  "id": "omarchy.nightlight",
+  "name": "Night Light",
+  "version": "1.0.0",
+  "author": "Omarchy",
+  "description": "Owns the hyprsunset night light temperature for the bar indicator and CLI.",
+  "kinds": [
+    "service"
+  ],
+  "entryPoints": {
+    "service": "Service.qml"
+  }
+}