feat: 添加 SourceHandler 接口

app/src/main/java/com/videoapp/tv/engine/SourceHandler.kt

@@ -0,0 +1,19 @@
+package com.videoapp.tv.engine
+
+import com.videoapp.tv.data.SearchResult
+
+interface SourceHandler {
+    val id: String
+    val displayName: String
+    val baseUrl: String
+
+    suspend fun search(
+        keyword: String,
+        onResult: suspend (List<SearchResult>) -> Unit,
+        onError: suspend (String) -> Unit
+    )
+
+    suspend fun extractVideos(detailUrl: String): List<PlaySource>
+
+    suspend fun resolvePlayUrl(playUrl: String): Pair<String?, String?>
+}