feat: extract proxy server from lfs-proxy.py into module

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/test_proxy.py

@@ -0,0 +1,50 @@
+import threading
+import http.client
+import time
+import pytest
+from unittest.mock import MagicMock, patch
+from jianda_proxy.proxy import create_server
+
+
+class TestCreateServer:
+    def test_creates_server_with_config(self):
+        config = {
+            "remote_domain": "git.example.com",
+            "upstream_host": "1.2.3.4",
+            "upstream_port": "9000",
+            "listen_host": "127.0.0.1",
+            "listen_port": "19999",
+        }
+        server = create_server(config)
+        assert server is not None
+        server.server_close()
+
+    def test_binds_to_correct_port(self):
+        config = {
+            "remote_domain": "git.example.com",
+            "upstream_host": "1.2.3.4",
+            "upstream_port": "9000",
+            "listen_host": "127.0.0.1",
+            "listen_port": "19998",
+        }
+        server = create_server(config)
+        assert server.server_address[1] == 19998
+        server.server_close()
+
+
+class TestProxyHandler:
+    def test_forward_proxy_mode(self):
+        from jianda_proxy.proxy import ProxyHandler
+
+        config = {
+            "remote_domain": "git.example.com",
+            "upstream_host": "1.2.3.4",
+            "upstream_port": "9000",
+            "listen_host": "127.0.0.1",
+            "listen_port": "19997",
+        }
+        server = create_server(config)
+        # Verify the handler has the correct config set as class attributes
+        assert hasattr(ProxyHandler, "REMOTE_DOMAIN")
+        assert ProxyHandler.REMOTE_DOMAIN == "git.example.com"
+        server.server_close()