Fix ruff lint findings

src/mcbladerf/capture.py

@@ -7,7 +7,6 @@ and computing power spectra from captured data.
 from __future__ import annotations
 
 import asyncio
-import struct
 import time
 from dataclasses import dataclass
 from pathlib import Path

src/mcbladerf/server.py

@@ -10,7 +10,7 @@ from typing import Annotated, Literal
 
 from fastmcp import FastMCP
 
-from . import device, capture, cli_fallback
+from . import capture, cli_fallback, device
 
 # Create FastMCP server instance
 mcp = FastMCP(