fix: correct FastMCP interface usage and resolve lint issues

- Fix FastMCP server interface to use correct mcp.run() instead of app.run(host, port)
- Remove unnecessary host and port parameters, use standard STDIO transport
- Fix all ruff lint issues including import sorting and blank lines
- Update ruff configuration to new lint configuration format
- Fix type annotation issues using Union syntax (int | None)
- Ensure uvx pypi-query-mcp-server works correctly
- All tests pass and lint checks pass

tests/test_basic.py

@@ -13,22 +13,22 @@ def test_version():
 def test_import():
     """Test that main modules can be imported."""
     from pypi_query_mcp.core import PyPIClient, VersionCompatibility
-    from pypi_query_mcp.server import app
-    
+    from pypi_query_mcp.server import mcp
+
     assert PyPIClient is not None
     assert VersionCompatibility is not None
-    assert app is not None
+    assert mcp is not None
 
 
 @pytest.mark.asyncio
 async def test_pypi_client_basic():
     """Test basic PyPI client functionality."""
     from pypi_query_mcp.core import PyPIClient
-    
+
     async with PyPIClient() as client:
         # Test that client can be created and closed
         assert client is not None
-        
+
         # Test cache clearing
         client.clear_cache()
 
@@ -36,24 +36,24 @@ async def test_pypi_client_basic():
 def test_version_compatibility():
     """Test version compatibility utility."""
     from pypi_query_mcp.core import VersionCompatibility
-    
+
     compat = VersionCompatibility()
-    
+
     # Test requires_python parsing
     spec = compat.parse_requires_python(">=3.8")
     assert spec is not None
-    
+
     # Test classifier extraction
     classifiers = [
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: Implementation :: CPython"
     ]
-    
+
     versions = compat.extract_python_versions_from_classifiers(classifiers)
     assert "3.8" in versions
     assert "3.9" in versions
-    
+
     implementations = compat.extract_python_implementations(classifiers)
     assert "CPython" in implementations
 
@@ -68,7 +68,7 @@ def test_mcp_tools_import():
         query_package_versions,
         suggest_python_version_for_packages,
     )
-    
+
     # Test that all tools are callable
     assert callable(query_package_info)
     assert callable(query_package_versions)