feat(settings): add toggle to disable system theme sync

Issue: #2279

Assets/Translations/en.json

@@ -944,6 +944,8 @@
       "predefined-desc": "Choose from a collection of predefined color schemes.",
       "predefined-generate-templates-label": "Generate templates for predefined schemes",
       "predefined-title": "Predefined color schemes",
+      "sync-gsettings-description": "Match the system theme to the active light or dark variant.",
+      "sync-gsettings-label": "Sync system theme",
       "templates-desc": "Apply colors to external applications.",
       "templates-filter-description": "Show templates from a specific category.",
       "templates-filter-label": "Filter by category",

Assets/settings-default.json

@@ -504,7 +504,8 @@
     "manualSunrise": "06:30",
     "manualSunset": "18:30",
     "generationMethod": "tonal-spot",
-    "monitorForColors": ""
+    "monitorForColors": "",
+    "syncGsettings": true
   },
   "templates": {
     "activeTemplates": [],

Assets/settings-search-index.json

@@ -524,6 +524,15 @@
     "subTab": 0,
     "subTabLabel": "common.colors"
   },
+  {
+    "labelKey": "panels.color-scheme.sync-gsettings-label",
+    "descriptionKey": "panels.color-scheme.sync-gsettings-description",
+    "widget": "NToggle",
+    "tab": 2,
+    "tabLabel": "panels.color-scheme.title",
+    "subTab": 0,
+    "subTabLabel": "common.colors"
+  },
   {
     "labelKey": "panels.color-scheme.dark-mode-mode-label",
     "descriptionKey": "panels.color-scheme.dark-mode-mode-description",