📄 docs(changelog): update for v0.2.1 release

Author: doubleinfinity

CHANGELOG.md

@@ -7,7 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
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-## [0.2.1] - 2025-
+## [0.2.1] - 2025-07-30
 
 ### Added
 - Storage mode configuration for product quantization: New storage_mode parameter in quantization config allows users to choose between:
@@ -37,9 +37,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Constructor parameter validation: Improved error handling for missing or invalid quantization parameters
 - Memory statistics accuracy: Corrected memory usage calculations based on actual storage mode behavior
 
-### Removed
-<!-- Add removals/deprecations here -->
-
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 ## [0.2.0] - 2025-07-28