Implement threading, logging, and CJK font support

Major improvements to GUI stability and internationalization:

- Fix GUI freezing by implementing threaded audio analysis
  - Add AudioAnalysisWorker thread for background processing
  - Progress signals with percentage updates
  - Thread-safe communication via Qt signals

- Add comprehensive CLI logging system
  - 5 log levels: ERROR, WARN, INFO, DEBUG, TRACE
  - Command line control: --log-level, --log-file
  - Real-time feedback during analysis operations

- Implement CJK font fallback system
  - FontManager with 3-tier fallback (custom → system → default)
  - Cross-platform CJK font detection (Windows/macOS/Linux)
  - Licensing-safe fonts/ directory with gitignored font files
  - Setup utility and comprehensive documentation

- Fix numpy array formatting issue with BPM detection
- Add progress indicators for long-running operations
- Preserve fonts directory structure with placeholder file

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

setup_fonts.py

@@ -0,0 +1,84 @@
+#!/usr/bin/env python3
+"""
+Font setup utility for CJK character support.
+Provides installation instructions and system font detection.
+"""
+
+import sys
+import platform
+from pathlib import Path
+
+# Add current directory to path to import our modules
+sys.path.insert(0, str(Path(__file__).parent))
+
+from font_manager import get_font_manager
+
+
+def main():
+    """Main font setup utility."""
+    print("=== Audio Analysis Toolkit - CJK Font Setup ===\n")
+    
+    # Get font manager and show current status
+    font_manager = get_font_manager()
+    
+    print("Current System Information:")
+    print(f"Platform: {platform.system()} {platform.release()}")
+    print(f"Python: {platform.python_version()}\n")
+    
+    # Try to initialize fonts
+    print("Initializing font system...")
+    success = font_manager.initialize()
+    
+    # Show detailed status
+    status = font_manager.get_status_report()
+    print(f"Font system status: {'✓ OK' if success else '⚠ Issues detected'}")
+    print(f"Matplotlib configured: {'✓' if status['matplotlib_configured'] else '✗'}")
+    print(f"Qt configured: {'✓' if status['qt_configured'] else '✗'}")
+    print(f"Custom fonts loaded: {status['custom_fonts_loaded']}")
+    
+    if status['custom_font_families']:
+        print(f"Custom font families: {', '.join(status['custom_font_families'])}")
+    
+    print(f"Fonts directory: {status['fonts_directory_path']}")
+    print(f"Directory exists: {'✓' if status['fonts_directory_exists'] else '✗'}")
+    print()
+    
+    # Show current matplotlib font configuration
+    print("Current matplotlib font stack:")
+    for i, font in enumerate(status['current_matplotlib_fonts'][:8], 1):
+        print(f"  {i}. {font}")
+    print()
+    
+    # Show installation instructions
+    print(font_manager.get_font_installation_instructions())
+    
+    # Test CJK character handling
+    print("\n=== Testing CJK Character Handling ===")
+    test_strings = [
+        "English Title",
+        "日本語のタイトル",  # Japanese
+        "中文标题",  # Chinese
+        "한국어 제목",  # Korean
+        "Test - テスト",  # Mixed
+    ]
+    
+    print("Testing font-safe title conversion:")
+    for test_str in test_strings:
+        safe_str = font_manager.get_cjk_safe_title(test_str)
+        status_indicator = "✓" if test_str == safe_str else "⚠"
+        print(f"  {status_indicator} '{test_str}' -> '{safe_str}'")
+    
+    print("\n=== Setup Complete ===")
+    if success:
+        print("Font system is ready for use!")
+        if status['custom_fonts_loaded'] == 0:
+            print("Consider adding CJK fonts to improve character display.")
+    else:
+        print("There were issues with font setup. Check the logs for details.")
+        print("The application will still work but CJK characters may not display correctly.")
+    
+    return 0 if success else 1
+
+
+if __name__ == '__main__':
+    sys.exit(main())