feat: 完成S02桥接能力并接通M09工作流文档解析闭环

- 新增统一文档解析桥接子域，封装 easy-agents 文档解析门面

- 支持工作流开始节点文件上传与素材选择的单文件对象输入

- DocNode 改为文档解析节点，PDF 走统一解析，非 PDF 保持默认读取

easyflow-ui-admin/app/src/locales/langs/en-US/aiWorkflow.json

@@ -26,7 +26,8 @@
   "result": "Result",
   "confirm": "For contents to be confirmed, please confirm first!",
   "completed": "Chain has been completed, please start a new one.",
-  "fileContentExtraction": "FileContentExtraction",
+  "fileContentExtraction": "Document Parsing",
+  "documentInput": "FileInput",
   "documentAddress": "DocumentAddress",
   "parsedText": "ParsedText",
   "resourceSync": "ResourceSync",
@@ -94,7 +95,8 @@
   "stageSave": "Save Check",
   "stagePreExecute": "Pre-execute Check",
   "descriptions": {
-    "fileContentExtraction": "Extract text content from PDF or Word documents, etc",
+    "fileContentExtraction": "Parse content from PDF, Word, and other document files",
+    "documentInput": "Upload a file or choose one from resources",
     "documentAddress": "Document URL address",
     "parsedText": "Parsed text content",
     "resourceSync": "Download resource files and save to system resource library",