[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/modules/main/advanced/Navigation.tsx

@@ -108,7 +108,7 @@ export const Navigation = () => {
                             "outline-none transition-all",
                             isFirst && "rounded-tl-xl",
                             isLast && "rounded-tr-xl",
-                            "focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-white/60",
+                            "focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-nb-gray-50/60",
                             isActive ? "text-netbird" : "text-nb-gray-400 hover:text-nb-gray-300",
                             isDisabled ? "cursor-not-allowed opacity-50" : "cursor-default",
                         )}