feat: ConfigRepository 添加 currentSourceId 存储

app/src/main/java/com/videoapp/tv/data/ConfigRepository.kt

@@ -30,6 +30,14 @@ class ConfigRepository(context: Context) {
         saveConfig(SiteConfig.default())
     }
 
+    fun getCurrentSourceId(): String {
+        return prefs.getString("current_source_id", "xb6v") ?: "xb6v"
+    }
+
+    fun setCurrentSourceId(id: String) {
+        prefs.edit().putString("current_source_id", id).apply()
+    }
+
     fun getPresets(): List<SitePreset> = SitePreset.PRESETS
 
     fun applyPreset(preset: SitePreset) {