added mcp server code

tests/cli/test_mcp_serve.py

@@ -0,0 +1,18 @@
+from docforge.cli.main import cli
+
+
+def test_serve_mcp(
+    cli_runner,
+    fake_mcp_docs,
+    mock_mcp_server_run,
+    monkeypatch,
+):
+    monkeypatch.chdir(fake_mcp_docs.parent)
+
+    result = cli_runner.invoke(
+        cli,
+        ["serve-mcp"],
+    )
+
+    assert result.exit_code == 0
+    assert mock_mcp_server_run()