[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/services/windowappearance_other.go

@@ -0,0 +1,16 @@
+//go:build !darwin && !windows && !android && !ios && !freebsd && !js
+
+package services
+
+import (
+	"unsafe"
+
+	"github.com/netbirdio/netbird/client/ui/preferences"
+)
+
+// setWindowAppearance is a no-op wherever there is no per-window appearance to
+// set, which is every target this file covers. On Linux the appearance is real
+// but app-wide, so setAppAppearance owns it instead; on the remaining Unix
+// targets there is no native theming to apply at all and setAppAppearance is
+// itself a stub (appappearance_other.go).
+func setWindowAppearance(unsafe.Pointer, preferences.Theme, bool) {}