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

pyproject.toml

@@ -51,6 +51,8 @@ pypi-query-mcp = "pypi_query_mcp.server:main"
 [tool.ruff]
 target-version = "py310"
 line-length = 88
+
+[tool.ruff.lint]
 select = [
     "E",  # pycodestyle errors
     "W",  # pycodestyle warnings
@@ -66,7 +68,7 @@ ignore = [
     "C901",  # too complex
 ]
 
-[tool.ruff.per-file-ignores]
+[tool.ruff.lint.per-file-ignores]
 "__init__.py" = ["F401"]
 
 [tool.mypy]