chore: prepare release v3.0.1

docs/releases/v3.0.1.md

@@ -0,0 +1,24 @@
+# MTG Python Deckbuilder v3.0.1
+
+## Summary
+Performance improvements and bug fixes for commander selection and display.
+
+## Fixed
+- **Color Identity Display**: Fixed commander color identity showing incorrectly as "Colorless (C)" for non-partner commanders in the summary panel
+
+## Performance
+- **Commander Selection Speed**: Dramatically improved response time from 4+ seconds to under 1 second
+  - Implemented intelligent caching for card data to eliminate redundant file loading
+  - Both commander data and full card database now cached with automatic refresh when data updates
+  - Past builds recommendations now 107x faster (0.86s → 0.008s)
+
+## For Users
+- Commander selection is now **much faster** - expect sub-second response times
+- Color identity labels in deck summaries now display correctly for all commanders
+- Web UI "Download from GitHub" button now includes the new commander cache file
+
+## Infrastructure
+- Created dedicated `commander_cards.parquet` file (472KB) for fast commander lookups
+- Updated GitHub Actions workflow to build and publish commander cache
+- Added commander cache download support in Docker entrypoint
+- Implemented three-level caching system for optimal performance