refactor: optimize backend module

domain/processors/base.py

@@ -0,0 +1,17 @@
+from typing import Protocol, Dict, Any
+
+
+class BaseProcessor(Protocol):
+    name: str
+    supported_exts: list
+    config_schema: list
+    produces_file: 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"""
+        ...
+
+# 约定：每个处理器需定义
+# PROCESSOR_TYPE: str
+# CONFIG_SCHEMA: list
+# PROCESSOR_FACTORY: Callable[[], BaseProcessor]