Docs: Add v2.0.1 changelog for chart improvements

Update all README files (English, Chinese, Russian, Ukrainian) with:
- Version 2.0.1 changelog section
- Document ComparisonChart timestamp-based grouping fix
- Note resolution of chart freezing issue on backend restart
- Highlight improved chronological data display
- Update last modified date to 2025-10-29

Bug fixes documented:
- Switched from cycle_number to timestamp grouping
- Fixed data alignment when backend resets cycles
- Enhanced debugging capabilities
- Improved historical data visualization

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

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

README.md

@@ -486,6 +486,14 @@ sudo apt-get install libta-lib0-dev
 
 ## 🔄 Changelog
 
+### v2.0.1 (2025-10-29)
+
+**Bug Fixes:**
+- ✅ Fixed ComparisonChart data processing logic - switched from cycle_number to timestamp grouping
+- ✅ Resolved chart freezing issue when backend restarts and cycle_number resets
+- ✅ Improved chart data display - now shows all historical data points chronologically
+- ✅ Enhanced debugging logs for better troubleshooting
+
 ### v2.0.0 (2025-10-28)
 
 **Major Updates:**
@@ -545,6 +553,6 @@ Issues and Pull Requests are welcome!
 
 ---
 
-**Last Updated**: 2025-10-28
+**Last Updated**: 2025-10-29
 
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