style: fix code formatting and linting issues

- Fix whitespace in docstrings and blank lines
- Remove unused variables in tests
- Rename unused loop variables to follow conventions
- All ruff checks now pass

Signed-off-by: Hal <hal.long@outlook.com>

examples/dependency_analysis_demo.py

@@ -17,7 +17,7 @@ from pypi_query_mcp.tools.package_downloader import download_package_with_depend
 async def analyze_pyside2_dependencies():
     """Analyze PySide2 dependencies for Python 3.10."""
     print("🔍 Analyzing PySide2 dependencies for Python 3.10...")
-    
+
     try:
         result = await resolve_package_dependencies(
             package_name="PySide2",
@@ -26,23 +26,23 @@ async def analyze_pyside2_dependencies():
             include_dev=False,
             max_depth=3
         )
-        
+
         print(f"✅ Successfully resolved dependencies for {result['package_name']}")
-        print(f"📊 Summary:")
+        print("📊 Summary:")
         summary = result['summary']
         print(f"   - Total packages: {summary['total_packages']}")
         print(f"   - Runtime dependencies: {summary['total_runtime_dependencies']}")
         print(f"   - Max depth: {summary['max_depth']}")
-        
-        print(f"\n📦 Package list:")
+
+        print("\n📦 Package list:")
         for i, pkg in enumerate(summary['package_list'][:10], 1):  # Show first 10
             print(f"   {i}. {pkg}")
-        
+
         if len(summary['package_list']) > 10:
             print(f"   ... and {len(summary['package_list']) - 10} more packages")
-        
+
         return result
-        
+
     except Exception as e:
         print(f"❌ Error analyzing dependencies: {e}")
         return None
@@ -51,9 +51,9 @@ async def analyze_pyside2_dependencies():
 async def download_pyside2_packages():
     """Download PySide2 and its dependencies."""
     print("\n📥 Downloading PySide2 and dependencies...")
-    
+
     download_dir = Path("./pyside2_downloads")
-    
+
     try:
         result = await download_package_with_dependencies(
             package_name="PySide2",
@@ -65,9 +65,9 @@ async def download_pyside2_packages():
             verify_checksums=True,
             max_depth=2  # Limit depth for demo
         )
-        
-        print(f"✅ Download completed!")
-        print(f"📊 Download Summary:")
+
+        print("✅ Download completed!")
+        print("📊 Download Summary:")
         summary = result['summary']
         print(f"   - Total packages: {summary['total_packages']}")
         print(f"   - Successful downloads: {summary['successful_downloads']}")
@@ -75,14 +75,14 @@ async def download_pyside2_packages():
         print(f"   - Total size: {summary['total_downloaded_size']:,} bytes")
         print(f"   - Success rate: {summary['success_rate']:.1f}%")
         print(f"   - Download directory: {summary['download_directory']}")
-        
+
         if result['failed_downloads']:
-            print(f"\n⚠️  Failed downloads:")
+            print("\n⚠️  Failed downloads:")
             for failure in result['failed_downloads']:
                 print(f"   - {failure['package']}: {failure['error']}")
-        
+
         return result
-        
+
     except Exception as e:
         print(f"❌ Error downloading packages: {e}")
         return None
@@ -91,7 +91,7 @@ async def download_pyside2_packages():
 async def analyze_small_package():
     """Analyze a smaller package for demonstration."""
     print("\n🔍 Analyzing 'click' package dependencies...")
-    
+
     try:
         result = await resolve_package_dependencies(
             package_name="click",
@@ -100,26 +100,26 @@ async def analyze_small_package():
             include_dev=False,
             max_depth=5
         )
-        
+
         print(f"✅ Successfully resolved dependencies for {result['package_name']}")
-        
+
         # Show detailed dependency tree
-        print(f"\n🌳 Dependency Tree:")
+        print("\n🌳 Dependency Tree:")
         dependency_tree = result['dependency_tree']
-        
-        for pkg_name, pkg_info in dependency_tree.items():
+
+        for _pkg_name, pkg_info in dependency_tree.items():
             indent = "  " * pkg_info['depth']
             print(f"{indent}- {pkg_info['name']} ({pkg_info['version']})")
-            
+
             runtime_deps = pkg_info['dependencies']['runtime']
             if runtime_deps:
                 for dep in runtime_deps[:3]:  # Show first 3 dependencies
                     print(f"{indent}  └─ {dep}")
                 if len(runtime_deps) > 3:
                     print(f"{indent}  └─ ... and {len(runtime_deps) - 3} more")
-        
+
         return result
-        
+
     except Exception as e:
         print(f"❌ Error analyzing dependencies: {e}")
         return None
@@ -129,26 +129,26 @@ async def main():
     """Main demonstration function."""
     print("🚀 PyPI Query MCP Server - Dependency Analysis Demo")
     print("=" * 60)
-    
+
     # Analyze a small package first
     click_result = await analyze_small_package()
-    
+
     # Analyze PySide2 dependencies
     pyside2_result = await analyze_pyside2_dependencies()
-    
+
     # Optionally download packages (commented out to avoid large downloads in demo)
     # download_result = await download_pyside2_packages()
-    
+
     print("\n" + "=" * 60)
     print("✨ Demo completed!")
-    
+
     if click_result:
-        print(f"📝 Click analysis saved to: click_dependencies.json")
+        print("📝 Click analysis saved to: click_dependencies.json")
         with open("click_dependencies.json", "w") as f:
             json.dump(click_result, f, indent=2)
-    
+
     if pyside2_result:
-        print(f"📝 PySide2 analysis saved to: pyside2_dependencies.json")
+        print("📝 PySide2 analysis saved to: pyside2_dependencies.json")
         with open("pyside2_dependencies.json", "w") as f:
             json.dump(pyside2_result, f, indent=2)