[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/MainExitNodeSwitcher.tsx

@@ -156,14 +156,14 @@ const ExitNodeTriggerCard = forwardRef<HTMLButtonElement, TriggerProps>(
                 disabled={disabled}
                 className={cn(
                     "flex w-full items-center gap-3 rounded-xl p-2.5 pr-5 text-left outline-none",
-                    "border border-nb-gray-920 bg-nb-gray-940",
+                    "border border-nb-gray-800 bg-nb-gray-940 dark:border-nb-gray-920",
                     "transition-colors duration-150",
                     "wails-no-draggable",
                     isFocusVisible &&
-                        "focus-visible:ring-2 focus-visible:ring-white/60 focus-visible:ring-offset-2 focus-visible:ring-offset-nb-gray-940",
+                        "focus-visible:ring-2 focus-visible:ring-nb-gray-50/60 focus-visible:ring-offset-2 focus-visible:ring-offset-nb-gray-940",
                     disabled
                         ? "cursor-not-allowed opacity-60"
-                        : "cursor-default hover:border-nb-gray-900 hover:bg-nb-gray-935 data-[state=open]:border-nb-gray-900 data-[state=open]:bg-nb-gray-935",
+                        : "cursor-default hover:border-nb-gray-700 hover:bg-nb-gray-935 data-[state=open]:border-nb-gray-700 data-[state=open]:bg-nb-gray-935 dark:hover:border-nb-gray-900 dark:data-[state=open]:border-nb-gray-900",
                     className,
                 )}
                 {...props}