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

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

README.zh-CN.md

@@ -565,6 +565,14 @@ sudo apt-get install libta-lib0-dev
 
 ## 🔄 更新日志
 
+### v2.0.1 (2025-10-29)
+
+**Bug修复:**
+- ✅ 修复ComparisonChart数据处理逻辑 - 从cycle_number分组改为timestamp分组
+- ✅ 解决后端重启导致cycle_number重置时图表冻结的问题
+- ✅ 改进图表数据显示 - 现在按时间顺序显示所有历史数据点
+- ✅ 增强调试日志，便于问题排查
+
 ### v2.0.0 (2025-10-28)
 
 **重大更新:**
@@ -624,6 +632,6 @@ MIT License - 详见 [LICENSE](LICENSE) 文件
 
 ---
 
-**最后更新**: 2025-10-28
+**最后更新**: 2025-10-29
 
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