feat(desktop): add resolvedTheme to theme provider

- Add resolvedTheme state to expose actual applied theme
- Listen for system theme changes when in "system" mode
- Fix mode toggle to show correct icon based on selected theme

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/desktop/src/renderer/src/components/mode-toggle.tsx

@@ -1,6 +1,5 @@
 import { HugeiconsIcon } from "@hugeicons/react"
 import { Sun03Icon, Moon02Icon, ComputerIcon } from "@hugeicons/core-free-icons"
-import { Button } from "@multica/ui/components/ui/button"
 import {
   DropdownMenu,
   DropdownMenuContent,
@@ -10,22 +9,15 @@ import {
 import { useTheme } from "./theme-provider"
 
 export function ModeToggle() {
-  const { setTheme } = useTheme()
+  const { theme, setTheme } = useTheme()
+
+  const icon = theme === "light" ? Sun03Icon : theme === "dark" ? Moon02Icon : ComputerIcon
 
   return (
     <DropdownMenu>
-      <DropdownMenuTrigger asChild>
-        <Button variant="ghost" size="icon" className="size-8">
-          <HugeiconsIcon
-            icon={Sun03Icon}
-            className="size-4 rotate-0 scale-100 transition-all dark:-rotate-90 dark:scale-0"
-          />
-          <HugeiconsIcon
-            icon={Moon02Icon}
-            className="absolute size-4 rotate-90 scale-0 transition-all dark:rotate-0 dark:scale-100"
-          />
-          <span className="sr-only">Toggle theme</span>
-        </Button>
+      <DropdownMenuTrigger className="inline-flex items-center justify-center size-8 rounded-md text-muted-foreground hover:bg-accent hover:text-accent-foreground transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring">
+        <HugeiconsIcon icon={icon} className="size-4" />
+        <span className="sr-only">Toggle theme</span>
       </DropdownMenuTrigger>
       <DropdownMenuContent align="end">
         <DropdownMenuItem onClick={() => setTheme("light")}>

apps/desktop/src/renderer/src/components/theme-provider.tsx

@@ -10,16 +10,24 @@ type ThemeProviderProps = {
 
 type ThemeProviderState = {
   theme: Theme
+  resolvedTheme: "light" | "dark"
   setTheme: (theme: Theme) => void
 }
 
 const initialState: ThemeProviderState = {
   theme: "system",
+  resolvedTheme: "light",
   setTheme: () => null,
 }
 
 const ThemeProviderContext = createContext<ThemeProviderState>(initialState)
 
+function getSystemTheme(): "light" | "dark" {
+  return window.matchMedia("(prefers-color-scheme: dark)").matches
+    ? "dark"
+    : "light"
+}
+
 export function ThemeProvider({
   children,
   defaultTheme = "system",
@@ -28,25 +36,39 @@ export function ThemeProvider({
   const [theme, setTheme] = useState<Theme>(
     () => (localStorage.getItem(storageKey) as Theme) || defaultTheme
   )
+  const [resolvedTheme, setResolvedTheme] = useState<"light" | "dark">(
+    () => (theme === "system" ? getSystemTheme() : theme)
+  )
 
   useEffect(() => {
     const root = window.document.documentElement
     root.classList.remove("light", "dark")
 
-    if (theme === "system") {
-      const systemTheme = window.matchMedia("(prefers-color-scheme: dark)")
-        .matches
-        ? "dark"
-        : "light"
-      root.classList.add(systemTheme)
-      return
+    const resolved = theme === "system" ? getSystemTheme() : theme
+    root.classList.add(resolved)
+    setResolvedTheme(resolved)
+  }, [theme])
+
+  // Listen for system theme changes
+  useEffect(() => {
+    if (theme !== "system") return
+
+    const mediaQuery = window.matchMedia("(prefers-color-scheme: dark)")
+    const handleChange = () => {
+      const resolved = getSystemTheme()
+      const root = window.document.documentElement
+      root.classList.remove("light", "dark")
+      root.classList.add(resolved)
+      setResolvedTheme(resolved)
     }
 
-    root.classList.add(theme)
+    mediaQuery.addEventListener("change", handleChange)
+    return () => mediaQuery.removeEventListener("change", handleChange)
   }, [theme])
 
   const value = {
     theme,
+    resolvedTheme,
     setTheme: (theme: Theme) => {
       localStorage.setItem(storageKey, theme)
       setTheme(theme)