fix: Resolve PDF processing (#267), How-To Guide (#242), Chinese README (#260) + code quality (#273)

Thanks @franklegolasyoung for the excellent work on the core fixes for issues #267, #242, and #260! 🙏

Your comprehensive approach to fixing PDF processing, expanding workflow detection, and improving the Chinese README documentation is much appreciated. I've added code quality fixes and comprehensive tests to ensure everything passes CI.

All 1266+ tests are now passing, and the issues are resolved! 🎉

tests/test_config_fetcher.py

@@ -1,7 +1,6 @@
 """Tests for config_fetcher module - automatic API config downloading."""
 
 import json
-from pathlib import Path
 from unittest.mock import Mock, patch
 
 import httpx
@@ -45,7 +44,7 @@ class TestFetchConfigFromApi:
         download_response.raise_for_status = Mock()
 
         # Setup mock to return different responses for different URLs
-        def get_side_effect(url, *args, **kwargs):
+        def get_side_effect(url, *_args, **_kwargs):
             if "download" in url:
                 return download_response
             return detail_response
@@ -133,16 +132,14 @@ class TestFetchConfigFromApi:
 
             detail_response = Mock()
             detail_response.status_code = 200
-            detail_response.json.return_value = {
-                "download_url": "https://api.example.com/download"
-            }
+            detail_response.json.return_value = {"download_url": "https://api.example.com/download"}
             detail_response.raise_for_status = Mock()
 
             download_response = Mock()
             download_response.json.return_value = {"name": "test"}
             download_response.raise_for_status = Mock()
 
-            def get_side_effect(url, *args, **kwargs):
+            def get_side_effect(url, *_args, **_kwargs):
                 if "download" in url:
                     return download_response
                 return detail_response