Add comprehensive documentation and usage instructions

- Added CLAUDE.md with detailed project documentation and roadmap
- Enhanced README.md with usage section for command line and GUI modes
- Updated with Claude Code credit
- Improved master_core.py with better song name handling and BPM display

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

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

README.md

@@ -1,5 +1,29 @@
 # uj-mastering-master
-Utility providing metrics to evaluate masterings.
+Utility providing metrics to evaluate masterings.  
+Now boosted by Claude Code.
 
 ## dependencies
-librosa, numpy, matplotlib, mutagen
+librosa, numpy, matplotlib, mutagen
+
+## usage
+
+### Command Line Analysis
+1. Edit `files.txt` to include paths to your audio files (MP3/WAV supported)
+   - Use `;` or `#` to comment out files
+   - One file path per line
+2. Run: `python master_core.py`
+   - Generates colorized power magnitude graphs for each file
+   - Displays BPM and song metadata
+   - Graphs show RMS power over time with adaptive scaling
+
+### GUI Mode (Experimental)
+Run: `python main.py`
+- Opens drag-and-drop interface
+- Currently displays dropped file paths
+- Analysis integration coming soon
+
+### Output
+- Interactive matplotlib graphs showing power levels over time
+- Color-coded visualization (autumn colormap)
+- Automatic headroom detection and scaling
+- Console output with BPM and metadata information