Update CHANGELOG.md for Bug#206: Add new features and fixes related to configuration-space parsing and performance data cleaning

Author: Kyotun

CHANGELOG.md

@@ -2,6 +2,19 @@
 
 Notable changes to Sparkle will be documented in this file.
 
+## [Unreleased]
+
+### Added
+- Broader coverage for configuration-space parsing to guard conditional/forbidden handling regressions. [Bug#206]
+
+### Changed
+- Comparison plots now filter out `NaN` points before choosing linear/log scale and rendering. [Bug#206]
+- IRACE parameter parsing now accepts categorical values whether they are double-quoted, single-quoted, or unquoted. [Bug#206]
+- Membership checks in parsed conditions/forbiddens now normalise single values into lists to ensure matching works as intended. [Bug#206]
+
+### Fixed
+- Performance data cleaning now drops `NaN` entries per sub-series and raises if a whole sub-series is `NaN`, avoiding silent failures. [Bug#206]
+
 ## [0.9.5.1] - 15/10/2025
 
 ### Added