feat(web-ui): seamless channel switch with dual video slots

web-ui/src/components/player/settings-dropdown.tsx

@@ -11,8 +11,8 @@ interface SettingsDropdownProps {
   onLocaleChange: (locale: Locale) => void;
   theme: ThemeMode;
   onThemeChange: (theme: ThemeMode) => void;
-  force16x9: boolean;
-  onForce16x9Change: (enabled: boolean) => void;
+  seamlessSwitch: boolean;
+  onSeamlessSwitchChange: (enabled: boolean) => void;
   mp2SoftDecode: boolean;
   onMp2SoftDecodeChange: (enabled: boolean) => void;
 }
@@ -36,8 +36,8 @@ function SettingsDropdownComponent({
   onLocaleChange,
   theme,
   onThemeChange,
-  force16x9,
-  onForce16x9Change,
+  seamlessSwitch,
+  onSeamlessSwitchChange,
   mp2SoftDecode,
   onMp2SoftDecodeChange,
 }: SettingsDropdownProps) {
@@ -104,10 +104,14 @@ function SettingsDropdownComponent({
               </select>
             </label>
 
-            {/* Force 16:9 Aspect Ratio Toggle */}
+            {/* Seamless channel/source switch (dual-slot preload) */}
             <div className="flex items-center justify-between px-1">
-              <span className="text-xs font-medium text-muted-foreground">{t("force16x9")}</span>
-              <Switch checked={force16x9} onCheckedChange={onForce16x9Change} aria-label={t("force16x9")} />
+              <span className="text-xs font-medium text-muted-foreground">{t("seamlessSwitch")}</span>
+              <Switch
+                checked={seamlessSwitch}
+                onCheckedChange={onSeamlessSwitchChange}
+                aria-label={t("seamlessSwitch")}
+              />
             </div>
 
             {/* MP2 Audio Software Decode Toggle */}