refactor(theme): drop unused MouseEvent param from setTheme

Now that the view transition animation is gone, setTheme no longer
needs click coordinates. Reduce the API surface to (theme: Theme) =>
void and simplify the call sites in mode-toggle and ThemeSettings.

src/components/mode-toggle.tsx

@@ -7,13 +7,11 @@ export function ModeToggle() {
   const { theme, setTheme } = useTheme();
   const { t } = useTranslation();
 
-  const toggleTheme = (event: React.MouseEvent) => {
-    // 如果当前是 dark 或 system（且系统是暗色），切换到 light
-    // 否则切换到 dark
+  const toggleTheme = () => {
     if (theme === "dark") {
-      setTheme("light", event);
+      setTheme("light");
     } else {
-      setTheme("dark", event);
+      setTheme("dark");
     }
   };
 

src/components/settings/ThemeSettings.tsx

@@ -19,21 +19,21 @@ export function ThemeSettings() {
       <div className="inline-flex gap-1 rounded-md border border-border-default bg-background p-1">
         <ThemeButton
           active={theme === "light"}
-          onClick={(e) => setTheme("light", e)}
+          onClick={() => setTheme("light")}
           icon={Sun}
         >
           {t("settings.themeLight")}
         </ThemeButton>
         <ThemeButton
           active={theme === "dark"}
-          onClick={(e) => setTheme("dark", e)}
+          onClick={() => setTheme("dark")}
           icon={Moon}
         >
           {t("settings.themeDark")}
         </ThemeButton>
         <ThemeButton
           active={theme === "system"}
-          onClick={(e) => setTheme("system", e)}
+          onClick={() => setTheme("system")}
           icon={Monitor}
         >
           {t("settings.themeSystem")}

src/components/theme-provider.tsx

@@ -17,7 +17,7 @@ interface ThemeProviderProps {
 
 interface ThemeContextValue {
   theme: Theme;
-  setTheme: (theme: Theme, event?: React.MouseEvent) => void;
+  setTheme: (theme: Theme) => void;
 }
 
 const ThemeProviderContext = createContext<ThemeContextValue | undefined>(