feat(video-library): implement video library processing and API integration

domain/processors/base.py

@@ -6,9 +6,11 @@ class BaseProcessor(Protocol):
     supported_exts: list
     config_schema: list
     produces_file: bool
+    supports_directory: bool
+    requires_input_bytes: bool
 
-    async def process(self, input_bytes: bytes, path: str, config: Dict[str, Any]) -> bytes:
-        """处理文件内容并返回处理后的内容"""
+    async def process(self, input_bytes: bytes, path: str, config: Dict[str, Any]) -> Any:
+        """处理文件内容/路径并返回结果。produces_file=True 时应返回 bytes/Response。"""
         ...
 
 # 约定：每个处理器需定义