chore: Update CHANGELOG.md

CHANGELOG.md

@@ -1,5 +1,14 @@
 # Changelog
 
+## 2.1.5
+
+- Added `CLAUDE_CODE_TMPDIR` environment variable to override the temp directory used for internal temp files, useful for environments with custom temp directory requirements
+
+## 2.1.4
+
+- Added `CLAUDE_CODE_DISABLE_BACKGROUND_TASKS` environment variable to disable all background task functionality including auto-backgrounding and the Ctrl+B shortcut
+- Fixed "Help improve Claude" setting fetch to refresh OAuth and retry when it fails due to a stale OAuth token
+
 ## 2.1.3
 
 - Merged slash commands and skills, simplifying the mental model with no change in behavior