[client] Add light mode with system, light, and dark theme options (#7344)

* desktop UI light mode

* Theme review fixes plus macOS window outline fix

* Windows runtime chrome re-theming plus apply serialization

* Windows chrome threading and theme event ordering fixes

* Darken toggle and setting sidebar text

* resolve theme appearance, apply on UI thread

* read theme once per window

* Re-assert Windows dark opt-in after SetTheme

* split app-wide GTK theming from per-window chrome

* Update Wails dependency and checksums

* KDE tray icon panel fix

* Five review fixes: theme ordering, cgo dedup, KDE panel resolution

* Path guard hardening, toggle contrast, windows comment

* non-vacuous escape tests

* Default view edits

* Polish settings nav, controls, borders, and disc

* Profiles settings boarder, modals, and buttons

* Additional edits based on feedback

* Switch colors away from slight blue hue

* Update missing lang

* Fix vertical tab active view

client/ui/frontend/src/components/switches/FancyToggleSwitch.tsx

@@ -36,7 +36,7 @@ export default function FancyToggleSwitch({
 
     if (loading) {
         const shimmer =
-            "text-transparent select-none rounded bg-[#25282d] box-decoration-clone animate-pulse";
+            "text-transparent select-none rounded bg-nb-gray-920 box-decoration-clone animate-pulse";
         return (
             <div
                 role={"status"}
@@ -58,7 +58,9 @@ export default function FancyToggleSwitch({
                     <div className={"mt-2 pr-1"}>
                         <div
                             aria-hidden={"true"}
-                            className={"h-[24px] w-[44px] animate-pulse rounded-full bg-[#25282d]"}
+                            className={
+                                "h-[24px] w-[44px] animate-pulse rounded-full bg-nb-gray-920"
+                            }
                         />
                     </div>
                 </div>